Process of electrophotographic imaging with layered light receiving member containing A-Si and Ge

ABSTRACT

There is provided an improved light receiving member comprising a substrate and a light receiving layer formed by laminating a first layer having photoconductivity which is constituted with an amorphous material containing silicon atoms as the main constituent atoms and germanium atoms, and a second layer constituted with an amorphous material containing silicon atoms, carbon atoms and an element for controlling the conductivity. The germanium atoms contained in the first layer is in the state of being unevenly distributed in the entire layer region or in the partial layer region adjacent to the substrate. The first layer may contain one or more kinds selected from an element for controlling the conductivity, oxygen atoms and nitrogen atoms in the entire layer region or in the partial layer region.

This is a division of application Ser. No. 011,505, filed February 5,1987, now U.S. Pat. No. 4,818,651.

FIELD OF THE INVENTION

This invention relates to an improved light receiving member sensitiveto electromagnetic waves such as light (such as ultra-violet rays,visible rays, infrared rays, X-rays and γ-rays).

BACKGROUND OF THE INVENTION

For the photoconductive material to constitute an image-forming memberfor use in solid image pickup device or electrophotography, or toconstitute a photoconductive layer for use in image-reading photosensor,it is required to be highly sensitive, to have a high S/N ratio[photocurrent (Ip)/dark current (Id)], to have absorption spectrumcharacteristics suited for an electromagnetic wave to be irradiated, tobe quickly responsive and to have a desired dark resistance. It is alsorequired to be not harmful to living things, especially man, upon theuse.

Other than these requirements, it is required to have a property ofremoving a residual image within a predetermined period of time in solidimage pickup device.

Particularly for image-forming members used in an electrophotographicmachine which is used as a business machine at the office, causing nopollution is highly important.

From these standpoints, the public attention has been focused on lightreceiving members comprising amorphous materials containing siliconatoms (hereinafter referred to as "A-Si"), for example, as disclosed inOffenlegungsschriftes Nos. 2,746,967 and 2,855,718 which disclose use ofthe light receiving member as an image-forming member inelectrophotography and in Offenlegungsschrift No. 2,933,411 whichdiscloses use of such light receiving member in an image-readingphotosensor.

For the conventional light receiving members comprising a-Si materials,there have been made improvements in their optical, electric andphotoconductive characteristics such as dark resistance,photosensitivity, and photoresponsiveness, use-environmentalcharacteristics, economic stability and durability.

However, it is still left to make further improvements in order to makesuch light receiving member practically usable.

For example, in the case where such conventional light receiving memberis used as an image-forming member in electrophotography with the goalof heightening the photosensitivity and dark resistance, there is oftenobserved a residual voltage on conventional light receiving member uponthe use, and when it is repeatedly used for a long period of time,fatigue due to the repeated use will be accumulated to cause theso-called ghost phenomena inviting residual images.

Further, in the preparation of the conventional light receiving memberusing an A-Si material, hydrogen atoms, halogen atoms such as fluorineatoms or chlorine atoms, elements for controlling the electricalconduction type such as boron atoms or phosphorus atoms, or other kindsof atoms for improving the characteristics are selectively incorporatedin a light receiving layer of the light receiving member as the layerconstituents.

However, the resulting light receiving layer sometimes becomesaccompanied with defects on the electrical characteristics,photoconductive characteristics and/or breakdown voltage according tothe way of the incorporation of said constituents to be employed.

That is, in the case of using the light receiving member having suchlight receiving layer, the life of a photocarrier generated in the layerwith the irradiation of light is not sufficient, the inhibition of acharge injection from the side of the substrate in a dark layer regionis not sufficiently carried out, and image defects likely due to a localbreakdown phenomenon (the so-called "white oval marks on half-tonecopies") or other image defects due to abrasion upon using a blade forthe cleaning (the so-called "white line") are apt to appear on thetransferred images on a paper sheet.

Further, in the case where the above light receiving member is used in ahumid atmosphere, or in the case where after being placed in thatatmosphere it is used, the so-called "image flow" sometimes appears onthe transferred images on a paper sheet.

Further in addition, in the case of forming a light receiving layer of aten and some mμ in thickness on an appropriate substrate to obtain alight receiving member, the resulting light receiving layer is likely toinvite undesired phenomena such as a thinner space being formed betweenthe bottom face and the surface of the substrate, the layer beingremoved from the substrate and a crack being generated within the layerfollowing the lapse of time after the light receiving member is takenout from the vacuum deposition chamber.

These phenomena are apt to occur in the case of using a cylindricalsubstrate to be usually used in the field of electrophotography.

Moreover, there have been proposed various so-called laser printersusing a semiconductor laser emitting ray as the light source inaccordance with the electrophotographic process. For such laser printer,there is an increased demand to provide an improved light receivingmember of having a satisfactorily rapid responsiveness to light in thelong wave region in order to enhance its function. In consequence, it isrequired not only to make a further improvement in an A-Si materialitself for use in forming the light receiving layer of the lightreceiving member but also to establish such a light receiving memberwhich will not invite any of the foregoing problems and to satisfy theforegoing demand.

SUMMARY OF THE INVENTION

The object of this invention is to provide a light receiving membercomprising a light receiving layer mainly composed of A-Si, free fromthe foregoing problems and capable of satisfying various kind ofrequirements.

That is, the main object of this invention is to provide a lightreceiving member comprising a light receiving layer constituted withA-Si in which electrical, optical and photoconductive properties arealways substantially stable and hardly depend on working circumstances,and which is excellent against optical fatigue, causes no degradationupon use, excellent in durability and moisture-resistance, exhibits noor minimal residual potential and provides easy production control.

Another object of this invention is to provide a light receiving membercomprising a light receiving layer composed of A-Si which has a highphotosensitivity in the entire visible region of light, particularly, anexcellent matching property with a semiconductor laser with rapid lightresponse.

Other object of this invention is to provide a light receiving membercomprising a light receiving layer composed of A-Si which has highphotosensitivity, high S/N ratio and high electrical voltagewithstanding property.

A further object of this invention is to provide a light receivingmember comprising a light receiving layer composed of A-Si which isexcellent in the close bondability between a support and a layerdisposed on the support or between each of the laminated layers, with adense and stable structural arrangement and of high layer quality.

A still further object of this invention is to provide a light receivingmember comprising a light receiving layer composed of A-Si which isexcellent in the close bondability between a support and a layerdisposed on the support or between each of the laminated layers, denseand stable in view of the structural arrangement and of high layerquality.

These and other objects, as well as the features of this invention willbecome apparent by the following descriptions of preferred embodimentsaccording to this invention while referring to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 4 are views of schematically illustrating representativeexamples of the light receiving member according to this invention.

FIGS. 5 through 13 are views illustrating the thicknesswise distributionof germanium atoms, the thicknesswise distribution of oxygen atoms,carbon atoms, or nitrogen atoms, or the thicknesswise distribution ofthe group III atoms or the group V atoms in the constituent layer of thelight receiving member according to this invention, the ordinaterepresenting the thickness of the layer and the abscissa representingthe distribution concentration of respective atoms.

FIG. 14 is a schematic explanatory view of a fabrication device by glowdischarge process as an example of the device for preparing the firstlayer and the second layer respectively of the light receiving memberaccording to this invention.

FIGS. 15 through 27 are views illustrating the variations in the gasflow rates in forming the light receiving layers according to thisinvention, wherein the ordinate represents the thickness of the layerand the abscissa represents the flow rate of a gas to be used.

DETAILED DESCRIPTION OF THE INVENTION

The present inventors have made detailed studies for overcoming theforegoing problems on the conventional light receiving members andattaining the objects as described above and, as a result, haveaccomplished this invention based on the finding as described below.

As a result of the studies focusing on materiality and practicalapplicability of a light receiving member comprising a light receivinglayer composed A-Si for use in electrophotography, solid image-pickupdevice and image-reading device, the present inventors have obtained thefollowing findings.

That is, the present inventors have found that in case where the lightreceiving layer composed of an amorphous material containing siliconatoms as the main constituent atoms is so structured as to have aparticular two-layer structure as later described, the resulting lightreceiving member provides many particularly excellent characteristicsespecially usable for electro-photography which are and superior to theconventional light receiving members in any of the requirements.

In more detail, the present inventors have found that when the lightreceiving layer is so structured as to have two layer structure usingthe so-called hydrogenated amorphous silicon-germanium material,halogenated amorphous silicon-germanium material or halogen-containinghydrogenated amorphous silicon-germanium material, namely, representedby amorphous materials containing silicon atoms as the main constituentatoms (Si), germanium atoms (Ge), and at least one of hydrogen atoms (H)and halogen atoms (X) [hereinafter referred to as "A-SiGe(H,X)"], theresulting light receiving member becomes such that brings about theforegoing unexpected effects.

Accordingly, the light receiving member to be provided according to thisinvention is characterized as comprising a substrate and a lightreceiving layer having a first layer of having photoconductivity whichis constituted of an amorphous material containing silicon atoms as themain constituent atoms and germanium atoms being unevenly distributed inthe entire layer region or in the partial layer region adjacent to thesubstrate and a second layer which is constituted with an amorphousmaterial containing silicon atoms as the main constituent atoms, carbonatoms and an element for controlling the conductivity.

As the amorphous material containing silicon atoms as the mainconstituent atoms to be used for the formation of the first layer, therecan be the so-called hydrogenated amorphous silicon, halogenatedamorphous silicon and halogen-containing hydrogenated amorphous silicon,namely, represented by amorphous materials containing silicon atoms (Si)as the main constituent atoms and at least one kind selected fromhydrogen atoms (H) and halogen atoms (X) [hereinafter referred to as"A-Si(H,X)"].

As the amorphous material containing silicon atoms as the mainconstituent atoms to be used for the formation of the second layer,there is used an amorphous material containing silicon atoms (Si) as themain constituent atoms, carbon atoms (C), and at least one kind selectedfrom hydrogen atoms (H) and halogen atoms (X) [hereinafter referred toas "A-SiC(H,X)"].

And, the first layer may contain at least one kind selected from anelement for controlling the conductivity, oxygen atoms and nitrogenatoms in the entire layer region or in the partial layer region.

As such element for controlling the conductivity, there can be theso-called impurities in the field of the semiconductor, and those usableherein include atoms belonging to the group III of the periodic tablethat provide p-type conductivity (hereinafter simply referred to as"group III atom") or atoms belonging to the group V of the periodictable that provide n-type conductivity (hereinafter simply referred toas "group V atom"). Specifically, the group III atoms can include B(boron), Al (aluminum), Ga (gallium), In (indium) and Ti (thallium), Band Ga being particularly preferred. The group V atoms can include, forexample, P (phosphorous), As (arsenic), Sb (antimony) and Bi (bismuth),P and As being particularly preferred.

In the case where both the first layer and the second layer contains anelement for controlling the conductivity, the kind of the element to becontained in the first layer can be the same as or different from thatto be contained in the second layer.

As the halogen atom (X) to be contained in the first layer and/or in thesecond layer in case where necessary, there can be fluorine, chlorine,bromine and iodine. Among these halogen atoms, fluorine and chlorine aremost preferred.

The first layer and/or the second layer may contain hydrogen atoms (H)where necessary. In that case, the amount of the hydrogen atoms (H), theamount of the halogen atoms (X) or the sum of the amounts for thehydrogen atoms and the halogen atoms (H+X) to be incorporated in thesecond layer is preferably 1×10⁻² to 4×10 atomic %, more preferably,5×10⁻² to 3×10 atomic %, and most preferably, 1×10⁻¹ to 25 atomic %.

The light receiving member according to this invention will now beexplained more specifically referring to the drawings. The descriptionis not intended to limit the scope of the invention.

FIGS. 1 through 4 are schematic views illustrating the typical layerstructures of the light receiving member of this invention, in which areshown the light receiving member 100, the substrate 101, the first layer102, and the second layer 103 having a free surface 104. And, thenumerals 105 through 110 stand for a layer region of the first layerrespectively.

Substrate (101)

The substrate 101 for use in this invention may either beelectroconductive or insulative. The electroconductive support caninclude, for example, metals such as NiCr, stainless steels, Al, Cr, Mo,Au, Nb, Ta, V, Ti, Pt and Pb or the alloys thereof.

The electrically insulative support can include, for example, films orsheets of synthetic resins such as polyester, polyethylene,polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride,polyvinylidene chloride, polystyrene, and polyamide, glass, ceramic andpaper. It is preferred that the electrically insulative substrate isapplied with electroconductive treatment to at least one of the surfacesthereof and disposed with a light receiving layer on the thus treatedsurface.

In the case of glass, for instance, electroconductivity is applied bydisposing, at the surface thereof, a thin film made of NiCr, Al, Cr, Mo,Au, Ir, Nb, Ta, V, Ti, Pt, Pd, In₂ O₃, SnO₂, ITO (In₂ O₃ +SnO₂), etc. Inthe case of the synthetic resin film such as a polyester film, theelectroconductivity is provided to the surface by disposing a thin filmof metal such as NiCr, Al, Ag, Pv, Zn, Ni, Au, Cr, Mo, Ir, Nb, Ta, V, Tland Pt by means of vacuum deposition, electron beam vapor deposition,sputtering, etc., or applying lamination with the metal to the surface.The substrate may be of any configuration such as cylindrical, belt-likeor plate-like shape, which can be properly determined depending on theapplication uses. For instance, in the case of using the light receivingmember shown in FIG. 1 as image forming member for use in electronicphotography, it is desirably configurated into an endless belt orcylindrical form for continuous high speed reproduction. The thicknessof the substrate member is properly determined so that the lightreceiving member as desired can be formed. In the event that flexibilityis required for the light receiving member, it can be made as thin aspossible within a range capable of sufficiently providing the functionas the substrate. However, the thickness is usually greater than 10 μmin view of the fabrication and handling or mechanical strength of thesubstrate.

First Layer (102)

The first layer 102 is disposed between the substrate 101 and the secondlayer 103 as shown in any of FIGS. 1 through 4.

Basically, the first layer 102 is composed of A-Si(H,X) which containsgermanium atoms in the state of being distributed unevenly in the entirelayer region or in the partial layer region adjacent to the substrate101 (Herein or hereinafter, the uneven distribution means that thedistribution of the related atoms in the layer is uniform in thedirection parallel to the surface of the substrate but is uneven in thethickness direction).

The purpose of incorporating germanium atoms in the first layer of thelight receiving member according to this invention is chiefly for theimprovement of an absorption spectrum property in the long wavelengthregion of the light receiving member.

That is, the light receiving member according to this invention becomesto give excellent various properties by incorporating germanium atoms inthe first layer. Particularly, it becomes more sensitive to light ofwavelengths broadly ranging from short wavelength to long wavelengthcovering visible light and it also becomes quickly responsive to light.

This effect becomes more significant when a semiconductor laser emittingray is used as the light source.

In the first layer of the light receiving member according to thisinvention, it may contain germanium atoms either in the entire layerregion or in the partial layer region adjacent to the substrate.

In the latter case, the first layer becomes to have a layer constitutionthat a constituent layer containing germanium atoms and anotherconstituent layer not containing germanium atoms are laminated in thisorder from the side of the substrate.

FIG. 2 shows the latter case in which are shown the substrate 101, thefirst layer 102 having a first constituent layer region 105 which isconstituted with A-Si(H,X) containing germanium atoms (hereinafterreferred to as "A-SiGe(H,X)") and a second constituent layer region 106which is constituted with A-Si(H,X) not containing germanium atoms.

And either in the case where germanium atoms are incorporated in theentire layer region or in the case where incorporated only in thepartial layer region, germanium atoms are distributed unevenly in thefirst layer 102 or the first constituent layer region 105.

In order to bring about desired objective characteristics by theincorporation of germanium atoms in the first layer 102 or in the firstconstituent layer region 105, various appropriate distributing statesmay be taken upon desired requirements.

For example, when germanium atoms are so distributed in the first layer102 or in the first constituent layer region 105 that their distributingconcentration is decreased thicknesswise toward the second layer 103from the side of the substrate, the affinity of the first layer 102 withthe second layer 103 becomes improved. And, when the distributingconcentration of germanium atoms are extremely heightened in the layerregion 105 adjacent to the substrate, the light of long wavelength,which can be hardly absorbed in the constituent layer or the layerregion near the free surface side of the light receiving layer when alight of long wavelength such as a semiconductor emitting ray is used asthe light source, can be substantially and completely absorbed in theconstituent layer or in the layer region respectively adjacent to thesupport for the light receiving layer. And this is directed to preventthe interference caused by the light reflected from the surface of thesubstrate.

As above explained, in the first layer of the light receiving memberaccording to this invention, germanium atoms is distributed unevenly andcontinuously in the direction of the layer thickness in the entire layerregion or the partial constituent layer region.

In the following, an explanation is made of the typical examples whengermanium atoms are so distributed that their thicknesswise distributingconcentration is decreased toward the interface with the second layerfrom the side of the substrate, with reference to FIGS. 5 through 13.

In FIGS. 5 through 13, the abscissa represents the distributionconcentration C of germanium atoms and the ordinate represents thethickness of the first layer 102 or the first constituent layer region105; and t_(B) represents the interface position between the substrateand the first layer 102 or the first constituent layer region 105 andt_(T) represents the interface position between the first layer 102 andthe second layer 103, or the interface position between the firstconstituent layer region 105 and the second constituent layer region106.

FIG. 5 shows the first typical example of the thicknesswise distributionof germanium atoms in the first layer or first constituent layer region.In this example, the germanium atoms are distributed in the way that theconcentration C remains constant at a value C₁ in the range fromposition t_(B) to position t₁, and the concentration C gradually andcontinuously decreases from C₂ in the range from position t₁ to positiont_(T), where the concentration of the germanium atoms becomes C₃.

In the example shown in FIG. 6, the distribution concentration C of thegermanium atoms contained in the first layer or the first constituentlayer region is such that concentration C₄ at position t_(B)continuously decreases to concentration C₅ at position t_(T).

In the example shown in FIG. 7, the distribution concentration C of thegermanium atoms is such that concentration C₆ remains constant in therange from position t_(B) and position t₂ and it gradually andcontinuously decreases in the range from position t₂ and position t_(T).The concentration at position t_(T) is substantially zero.

In the example shown in FIG. 8, the distribution concentration C of thegermanium atoms is such that concentration C₈ gradually and continuouslydecreases in the range from position t_(B) and position t_(T), at whichit is substantially zero.

In the example shown in FIG. 9, the distribution concentration C of thegermanium atoms is such that concentration C₉ remains constant in therange from position t_(B) to position t₃, and concentration C₈ linearlydecreases to concentration C₁₀ in the range from position t₃ to positiont_(T).

In the example shown in FIG. 10, the distribution concentration C of thegermanium atoms is such that concentration C₁₁ remains constant in therange from position t_(B) and position t₄ and it linearly decreases toC₁₄ in the range from position t₄ to position t_(T).

In the example shown in FIG. 11, the distribution concentration C of thegermanium atoms is such that concentration C₁₄ linearly decreases in therange from position t_(B) to position t_(T), at which the concentrationis substantially zero.

In the example shown in FIG. 12, the distribution concentration C of thegermanium atoms is such that concentration C₁₅ linearly decreases toconcentration C₁₆ in the range from position t_(B) to position t₅ andconcentration C₁₆ remains constant in the range from position t₅ toposition t_(T).

Finally, in the example shown in FIG. 13, the distribution concentrationC of the germanium atoms is such that concentration C₁₇ at positiont_(B) slowly decreases and then sharply decreases to concentration C₁₈in the range from position t_(B) to position t₆. In the range fromposition t₆ to position t₇, the concentration sharply decreases at firstand slowly decreases to C₁₉ at position t₇. The concentration slowlydecreases between position t₇ and position t₈, at which theconcentration is C₂₀. Concentration C₂₀ slowly decreases tosubstantially zero between position t₈ and position t_(T).

Several examples of the thicknesswise distribution of germanium atoms inthe first layer 102 or in the first constituent layer region 105 havebeen illustrated in FIGS. 5 through 13. In the light receiving member ofthis invention, the concentration of germanium atoms in the such layeror layer region should preferably be high at the position adjacent tothe substrate and considerably low at the position adjacent to theinterface with the second layer 103.

In other words, it is desirable that the light receiving layerconstituting the light receiving member of this invention have a regionadjacent to the substrate in which germanium atoms are locally containedat a relatively high concentration.

Such a local region in the light receiving member of this inventionshould preferably be formed within 5 μm from the interface between thesubstrate and the first layer.

And, in the case where such local region is not present, it is desirablethat the maximum concentration C_(max) is positioned within 5 μm fromthe interface with the substrate.

In the light receiving member of this invention, the amount of germaniumatoms in the first layer should be properly determined so that theobject of the invention is effectively achieved.

In the case of incorporating germanium atoms in the entire layer regionof the first layer, it is preferably 1 to 6×10⁵ atomic ppm, morepreferably 10 to 3×10⁵ atomic ppm, and, most preferably 1×10² to 2×10⁵atomic ppm.

And, in the case of incorporating germanium atoms in the layer region ofthe first layer being adjacent to the substrate, it is preferably 1 to9.5×10⁵ atomic ppm, more preferably 100 to 8×10⁵ atomic ppm, and, mostpreferably, 100 to 7×10⁵ atomic ppm.

For the thickness of the first constituent layer region 105 containinggermanium atoms and that of the second constituent layer region 106 notcontaining germanium atoms, they are important factors for effectivelyattaining the foregoing objects of this invention, and are desirablydetermined so that the resulting light receiving member becomesaccompanied with desired many practically applicable characteristics.

The thickness (T_(B)) of the constituent layer region 105 containinggermanium atoms is preferably 3×10⁻³ to 50 μm, more preferably 4×10⁻³ to40 μm, and, most preferably, 5×10⁻³ to 30 μm.

As for the thickness (T) of the constituent layer region 106, it ispreferably 0.5 to 90 μm, more preferably 1 to 80 μm, and, mostpreferably, 2 to 50 μm.

And, the sum (T_(B) +T) of the thickness (T_(B)) for the former layerregion and that (T) for the latter layer region is desirably determinedbased on relative and organic relationships with the characteristicsrequired for the first layer 102.

It is preferably 1 to 10 μm, more preferably 1 to 80 μm, and, mostpreferably, 2 to 50 μm.

Further, for the relationship of the layer thickness T_(B) and the layerthickness T, it is preferred to satisfy the equation: T_(B) /T≦1, morepreferred to satisfy the equation: T_(B) /T≦0.9, and, most preferred tosatisfy the equation: T_(B) /T≦0.8.

In addition, for the layer thickness (T_(B)) of the layer regioncontaining germanium atoms, it is necessary to be determined based onthe amount of the germanium atoms to be contained in that layer region.For example, in the case where the amount of the germanium atoms to becontained therein is more than 1×10⁵ atomic ppm, the layer thicknessT_(B) is desired to be remarkably large.

Specifically, it is preferably less than 30 μm, more preferably lessthan 25 μm, and, most preferably, less than 20 μm.

In the first layer 102 of the light receiving member of this invention,an element for controlling the conductivity is incorporated aiming atthe control for the conduction type and/or conductivity of that layer,the provision of a charge injection inhibition layer at the substrateside of that layer, the enhancement of movement of electrons of thefirst layer 102 and the second layer 103, the formation of a compositionpart between the first layer and the second layer to increase anapparent dark resistance and the like. And the element for controllingthe conductivity may be contained in the first layer in a uniformly orunevenly distributed state in the entire or partial layer region.

As the element for controlling the conductivity, so-called impurities inthe field of the semiconductor can be mentioned and those usable hereincan include atoms belonging to the group III of the periodic table thatprovide p-type conductivity (hereinafter simply referred to as "groupIII atoms") or atoms belonging to the group V of the periodic table thatprovide n-type conductivity (hereinafter simply referred to as "group Vatoms"). Specifically, the group III atoms can include B (boron), Al(aluminum), Ga (gallium), In (indium), and Tl (thallium), B and Ga beingparticularly preferred. The group V atoms can include, for example, P(phosphorus), As (arsenic), Sb (antimony), and Bi (bismuth), P and Sbbeing particularly preferred.

In the case of incorporating the group III or group V atoms as theelement for controlling the conductivity into the first layer of thelight receiving member according to this invention, they are containedin the entire layer region or partial layer region depending on thepurpose or the expected effects as described below and the content isalso varied.

That is, if the main purpose resides in the control for the conductiontype and/or conductivity of the photosensitive layer, the element iscontained in the entire layer region of the first layer, in which thecontent of group III or group V atoms may be relatively small and it ispreferably from 1×10⁻³ to 1×10³ atomic ppm, more preferably from 5×10⁻²to 5×10² atomic ppm, and most preferably, from 1×10⁻¹ to 5×10² atomicppm.

In the case of inocrporating the group III or group V atoms in auniformly or unevenly distributed state to a portion of the layer region105 in contact with the substrate as shown in FIG. 2, or the atoms arecontained such that the distribution density of the group III or group Vatoms in the direction of the layer thickness is higher on the sideadjacent to the substrate, the layer containing such group III or groupV atoms or the layer region containing the group III or group V atoms athigh concentration functions as a charge injection inhibition layer.That is, in the case of incorporating the group III atoms, movement ofelectrons injected from the side of the substrate into the first layercan effectively be inhibited upon applying the charging treatment of atpositive polarity at the free surface of the layer. While on the otherhand, in the case of incorporating the group III atoms, movement ofpositive holes injected from the side of the substrate into the firstlayer can effectively be inhibited. The content in this case isrelatively great. Specifically, it is generally from 30 to 5×10⁴ atomicppm, preferably from 50 to 1×10⁴ atomic ppm, and most suitably from1×10² to 5×10³ atomic ppm.

In order to further effectively attain the above purpose, for therelationship between the layer thickness (t) of the layer region 105 andthe layer thickness (t₀) of other layer region of the first layer, it ispreferred to satisfy the equation: t/t+t₀ ≦0.4, more preferred tosatisfy the equation: t/t+t₀ ≦0.35, and, most preferred to satisfy theequation: t/t+t₀ ≦0.30.

Specifically, the layer thickness of the layer region 105 is preferably3×10⁻³ to 10 μm, more preferably 4×10⁻³ to 8 μm, and, most preferably,5×10⁻³ to 5 μm.

Further, in order to improve the matching of energy level between thefirst layer 102 and the second layer 103 to thereby promote movement ofan electric charge between the two layers, the group III or group Vatoms are incorporated the partial layer region 107 adjacent to thesecond layer 103 as shown in FIG. 3 in a uniformly or unevenlydistributed state. The uneven incorporation of such atoms can be carriedout based on the typical examples for germanium atoms as shown in FIGS.5 through 13 or by properly modifying the examples. For example, thethicknesswise distributing concentration of the group III or group Vatoms is decreased toward the substrate side from the side of the secondlayer. In order to effectively attain the above purpose, the conductiontype of the element for controlling the conductivity to be contained inthe first layer is necessary to be the same as that of the element forcontrolling the conductivity to be contained in the second layer. Inthat case, when the layer thickness of the second layer is large and thedark resistance is high, the effects become significant. As for theamount of the group III or group V atoms to be contained is sufficientto be relatively small. Specifically, it is preferably 1×10⁻³ to 1×10³atomic ppm, more preferably 5×10⁻² to 5×10² atomic ppm, and, mostpreferably, 1×10⁻¹ to 2×10² atomic ppm.

Further, in order to improve the apparent dark resistance at the time ofelectrification process by purposely disposing a composition partiallypart between the first layer and the second layer, the partial layerregion 107 being adjacent to the second layer 103 as shown in FIG. 3, anelement having a different conduction type from the element forcontrolling the conductivity to be contained in the second layer isincorporated in a uniformly or unevenly distributed state.

In that case, the amount of the group III or group V atoms is sufficientto be relatively small. Specifically, it is preferably 1×10⁻³ to 1×10³atomic ppm, more preferably 5×10⁻² to 5×10² atomic ppm, and, mostpreferably, 1×10⁻¹ to 2×10² atomic ppm.

While the individual effects have been described above for thedistribution state of the group III or group V atoms, the distributionstate of the group III or group V atoms and the amount of the group IIIor group V atoms are, of course, combined properly as required forobtaining the light receiving member having performances capable ofattaining a desired purpose.

For instance, in the case of aiming at both the control of theconduction type and the disposition of a charge injection inhibitionlayer. The group III or group V atoms are distributed at a relativelyhigh distributing concentration in the layer region at the substrateside, and such atoms are distributed at a relatively low distributingconcentration in the interface side with the second layer, or such adistributed state that does not purposely contain such atoms in theinterface side with the second layer is established.

The first layer of the light receiving member of this invention may beincorporated with at least one kind selected from oxygen atoms andnitrogen atoms. This is effective in increasing the photosensitivity anddark resistance of the light receiving member and also in improvingadhesion between the substrate and the first layer or that between thefirst layer and the second layer.

In the case of incorporating at least one kind selected from oxygenatoms and nitrogen atoms into the first layer or its partial layerregion, it is performed at a uniform distribution or uneven distributionin the direction of the layer thickness depending on the purpose or theexpected effects as described above with reference to FIGS. 5 through 13for germanium atoms, and accordingly, the content is varied depending onthem.

That is, in the case of increasing the photosensitivity and the darkresistance of the first layer, they are contained at a uniformdistribution over the entire layer region of the first layer. In thiscase, the amount of at least one kind selected from oxygen atoms andnitrogen atoms contained in the first layer may be relatively small.

In the case of improving the adhesion between the substrate and thefirst layer, at least one kind selected from oxygen atoms and nitrogenatoms is contained uniformly in the layer region 105 constituting thefirst layer adjacent to the support or at least one kind selected fromoxygen atoms and nitrogen atoms is contained such that the distributionconcentration is higher at the end of the first layer on the side of thesubstrate.

In the case of improving the adhesion between the first layer and thesecond layer, at least one kind selected from oxygen atoms and nitrogenatoms are uniformly incorporated in the partial layer region 107adjacent to the second layer as shown in FIG. 3, or they areincorporated in such an unevenly distributed state that theirdistributing concentration becomes higher in the layer region of thefirst layer in the second layer side. Further, the above objects can beattained also by uniformly incorporating at least one kind selected fromoxygen atoms and nitrogen atoms in the second layer as later described.

In any case, in order to secure the promotion of the adhesion, it isdesirable for the amount of oxygen atoms and/or nitrogen atoms to beincorporated to be relatively high.

The uneven incorporation of oxygen atoms and/or nitrogen atoms can becarried out based on the typical examples as described above forgermanium atoms with reference to FIGS. 5 through 13.

That is, according to a desired purpose, it is possible to decreasetheir distributing concentration from the second layer side toward thesubstrate side. In addition, a further improvement in the above adhesionbetween the substrate and the first layer can be achieved byestablishing a localized region in the first layer in which oxygen atomsand/or nitrogen atoms are contained at a high concentration. Explainingthe localized region with reference to FIGS. 5 through 13, it isdesirable to be disposed within 5 μm from the position of interfacet_(B). And such localized region may be either the entire of the partiallayer region 105 or a part of the partial layer region 105 respectivelycontaining oxygen atoms and/or nitrogen atoms.

While the individual effects have been described above for thedistributing state of oxygen atoms and/or nitrogen atoms, thedistributing state of the oxygen atoms and/or the nitrogen atoms andtheir amount are, of course, combined properly as required for obtainingthe light receiving member having performances capable of attaining adesired purpose.

For instance, in the case of aiming at both the promotion of theadhesion between the substrate and the first layer and the improvementsin the photosensitivity and dark resistance, oxygen atoms and/ornitrogen atoms are distributed at a relatively high distributingconcentration in the layer region at the substrate side, and such atomsare distributed at a relatively low distributing concentration in theinterface side of the first layer with the second layer, or such adistributed state that does not purposely contain such atoms in theinterface side of the first layer with the second layer.

The amount of oxygen atoms and/or nitrogen atoms to be contained in thefirst layer is properly determined not only depending on thecharacteristics required for the first layer itself but also having theregards on the related factors, for example, relative and organicrelationships with an adjacent layer or with the properties of thesubstrate. This is so especially where oxygen atoms and/or nitrogenatoms are incorporated in the partial layer region of the first layeradjacent to the substrate or the second layer.

It is preferably 1×10⁻³ to 50 atomic %, more preferably 2×10⁻³ to 40atomic %, and, most preferably, 3×10⁻³ to 30 atomic %.

In the case where the entire layer region of the first layer isincorporated with oxygen atoms and/or nitrogen atoms or in the casewhere the proportion occupied by the partial layer region containingoxygen atoms and/or nitrogen atoms in the first layer is sufficientlylarge, the maximum amount of the oxygen atoms and/or the nitrogen atomsto be contained is desirable to be lower enough than the above value.For instance, in the case where the layer thickness of the partial layerregion containing oxygen atoms and/or nitrogen atoms corresponds a valueof more than 2/5 of the layer thickness of the first layer, the upperlimit of the amount of the oxygen atoms and/or the nitrogen atoms to becontained in that partial layer region is preferably less than 30 atomic%, more preferably less than 20 atomic %, and, most preferably, lessthan 10 atomic %.

Further, in the case where a localized region containing oxygen atomsand/or nitrogen atoms at a high concentration is established, themaximum concentration C_(max) for the distributing concentration of theoxygen atoms and/or the nitrogen atoms in a thicknesswise distributedstate is preferably more than 500 atomic ppm, more preferably more than800 atomic ppm, and, most preferably, more than 1000 atomic ppm.

As above explained, the first layer of the light receiving member ofthis invention is incorporated with germanium atoms, the group III orgroup V atoms, and optionally, oxygen atoms and/or nitrogen atoms, butthese atoms are selectively incorporated in that layer based on relativeand organic relationships of the amount and the distributing state ofeach kind of the atoms. And, the layer region in which each kind of theatoms is incorporated may be different or partially overlapped.

Now, the typical example will be explained with reference to FIG. 4, butthe invention is not intended to limit the scope only thereto.

Referring FIG. 4, there is shown the light receiving member 100 whichcomprises the substrate 101, the first layer constituted by firstconstituent layer region 108, second constituent layer region 109 andthird constituent layer region 110, and the second layer 103 having thefree surface 104. In this typical example, the layer region 108 containsgermanium atoms, the group III or group V atoms, and oxygen atoms. Thelayer region 109 which is disposed on the layer region 108 containsgermanium atoms and oxygen atoms but neither the group III atoms nor thegroup V atoms. The layer region 110 contains only germanium atoms. Inany of the above-mentioned layer regions, the germanium atoms are in theentire of the layer region in an unevenly distributed state.

In this invention, the layer thickness of the first layer is animportant factor for effectively attaining the objects of this inventionand should be properly determined having due regards for obtaining alight receiving member having desirable characteristics.

In view of the above, it is preferably 1 to 100 μm, more preferably 1 to80 μm, and, most preferably 2 to 50 μm.

Second Layer (103)

The second layer 103 having the free surface 104 is disposed on thefirst layer 102 to attain the objects chiefly of moisture resistance,deterioration resistance upon repeating use, electrical voltagewithstanding property, use environmental characteristics and durabilityfor the light receiving member according to this invention.

The second layer is formed of an amorphous material containing siliconatoms as the constituent atoms which are also contained in the layerconstituent amorphous material for the first layer, so that the chemicalstability at the interface between the two layers is sufficientlysecured.

Typically, the surface layer is formed of an amorphous materialcontaining silicon atoms, carbon atoms, and hydrogen atoms and/orhalogen atoms in case where necessary [hereinafter referred to as"A-SiC(H,X)"].

The foregoing objects for the second layer can be effectively attainedby introducing carbon atoms structurally into the second layer.

And, the case of introducing carbon atoms structurally into the secondlayer, following the increase in the amount of carbon atoms to beintroduced, the above-mentioned characteristics will be promoted, butits layer quality and its electric and mechanical characteristics willbe decreased if the amount is excessive.

In view of the above, the amount of carbon atoms to be contained in thesecond layer is preferably 1×10⁻³ to 90 atomic %, more preferably 1 to90 atomic %, and, most preferably, 10 to 80 atomic %.

For the layer thickness of the second layer, it is desirable to bethickened. But the problem due to generation of a residual voltage willoccur in the case where it is excessively thick. In view of this, byincorporating an element for controlling the conductivity such as thegroup III atom or the group V atom in the second layer, the occurrenceof the above problem can be effectively prevented beforehand. In thatcase, in addition to the above effect, the second layer becomes suchthat is free from any problem due to, for example, so-called scratcheswhich will be caused by a cleaning means such as blade and which invitedefects on the transferred images in the case of using the lightreceiving member in electrophotography.

In view of the above, the incorporation of the group III or group Vatoms in the second layer is quite beneficial for forming the secondlayer having appropriate properties as required.

And, the amount of the group III or group V atoms to be contained in thesecond layer is preferably 1.0 to 1×10⁴ atomic ppm, more preferably 10to 5×10³ atomic ppm, and, most preferably, 10² to 5×10³ atomic ppm.

The formation of the second layer should be carefully carried out sothat the resulting second layer becomes such that brings about thecharacteristics required therefor.

By the way, the texture state of a layer constituting material whichcontains silicon atoms, carbon atoms, hydrogen atoms and/or halogenatoms, and the group III atoms or the group V atoms takes from crystalstate to amorphous state which show from a semiconductive property to aninsulative property for the electric and physical property and whichshow from a photoconductive property to a nonphotoconductive propertyfor the optical and electric property upon the layer forming conditionsand the amount of such atoms to be incorporated in the layer to beformed.

In view of the above, for the formation of a desirable layer to be thesecond layer 103 which has the required characteristics, it is requiredto choose appropriate layer forming conditions and an appropriate amountfor each kind of atoms to be incorporated so that such second layer maybe effectively formed.

For instance, in the case of disposing the second layer 103 aimingchiefly at the improvement in the electrical voltage withstandingproperty, that layer is formed of such an amorphous material thatinvites a significant electrically-insulative performance on theresulting layer.

Further, in the case of disposing the second layer 103 aiming chiefly atthe improvement in the deterioration resistance upon repeating use, theusing characteristics and the use environmental characteristics, thatlayer is formed of such an amorphous material that eases the foregoingelectrically-insulative property to some extent but bring about certainphotosensitivity or the resulting layer.

Further in addition, the adhesion of the second layer 103 with the firstlayer 102 may be further improved by incorporating oxygen atoms and/ornitrogen atoms in the second layer in a uniformly distributed state.

For the light receiving member of this invention, the layer thickness ofthe second layer is also an important factor for effectively attainingthe objects of this invention.

Therefore, it is appropriately determined depending upon the desiredpurpose.

It is, however, also necessary that the layer thickness be determined inview of relative and organic relationships in accordance with theamounts of silicon atoms, carbon atoms, hydrogen atoms, halogen atoms,the group III atoms, and the group V atoms to be contained in the secondlayer and the characteristics required in relationship with thethickness of the first layer.

Further, it should be determined also in economical viewpoints such asproductivity or mass productivity.

In view of the above, the layer thickness of the second layer ispreferably 3×10⁻³ to 30 μm, more preferably 4×10⁻³ to 20 μm, and, mostpreferably, 5×10⁻³ to 10 μm.

As above explained, since the light receiving member of this inventionis structured by laminating a special first layer and a special secondlayer on a substrate, almost all the problems which are often found onthe conventional light receiving member can be effectively overcome.

Further, the light receiving member of this invention exhibits not onlysignificantly improved electric, optical and photoconductivecharacteristics, but also significantly improved electrical voltagewithstanding property and use environmental characteristics. Furthe inaddition, the light receiving member of this invention has a highphotosensitivity in the entire visible region of light, particularly, anexcellent matching property with a semiconductor laser and shows rapidlight response.

And, when the light receiving member is applied for use inelectrophotography, it gives no undesired effects at all of the residualvoltage to the image formation, but gives stable electrical propertieshigh sensitivity and high S/N ratio, excellent light fastness andproperty for repeating use, high image density and clear half tone. Atit can provide high quality image with high resolution powerrepeatingly.

Preparation of First Layer (102) and Second Layer (103)

The method of forming the light receiving layer of the light receivingmember will be now explained.

Each of the first layer 102 and the second layer 103 to constitute thelight receiving layer of the light receiving member of this invention isproperly prepared by vacuum deposition method utilizing the dischargephenomena such as glow discharging, sputtering and ion plating methodswherein relevant gaseous starting materials are selectively used.

These production methods are properly used selectively depending on thefactors such as the manufacturing conditions, the installation costrequired, production scale and properties required for the lightreceiving members to be prepared. The glow discharging method orsputtering method is suitable since the control for the condition uponpreparing the layers having desired properties are relatively easy, andhydrogen atoms, halogen atoms and other atoms can be introduced easilytogether with silicon atoms. The glow discharging method and thesputtering method may be used together in one identical system.

Preparation of First Layer (102)

Basically, when a layer constituted with A-Si(H,X) is formed, forexample, by the glow discharging method, gaseous starting materialcapable of supplying silicon atoms (Si) are introduced together withgaseous starting material for introducing hydrogen atoms (H) and/orhalogen atoms (X) into a deposition chamber the inside pressure of whichcan be reduced, glow discharge is generated in the deposition chamber,and a layer composed of A-Si(H,X) is formed on the surface of asubstrate placed in the deposition chamber.

The gaseous starting material for supplying Si can include gaseous orgasifiable silicon hydrides (silanes) such as SiH₄, Si₂ H₆, Si₃ H₈, Si₄H₁₀, etc., SiH₄ and Si₂ H₆ being particularly preferred in view of theeasy layer forming work and the good efficiency for the supply of Si.

Further, various halogen compounds can be mentioned as the gaseousstarting material for introducing the halogen atoms, and gaseous orgasifiable halogen compounds, for example, gaseous halogen, halides,inter-halogen compounds and halogen-substituted silane derivatives arepreferred. Specifically, they can include halogen gas such as offluorine, chlorine, bromine, and iodine; inter-halogen compounds such asBrF, ClF, ClF₃, BrF₂, BrF₃ IF₇, ICl, IBr, etc.; and silicon halides suchas SiF₄, Si₂ F₆, SiCl₄, and SiBr₄. The use of the gaseous or gasifiablesilicon halide as described above is particularly advantageous since thelayer constituted with halogen atom-containing A-Si:H can be formed withno additional use of the gaseous starting silicon hydride material forsupplying Si.

In the case of forming a layer constituted with an amorphous materialcontaining halogen atoms, typically, a mixture of a gaseous siliconhalide substance as the starting material for supplying Si and a gassuch as Ar, H₂ and He is introduced into the deposition chamber having asubstrate in a predetermined mixing ratio and at a predetermined gasflow rate, and the thus introduced gases are exposed to the action ofglow discharge to thereby cause a gas plasma resulting in forming saidlayer on the substrate.

And, for incorporating hydrogen atoms in said layer, an appropriategaseous starting material for supplying hydrogen atoms can beadditionally used.

Now, the gaseous starting material usable for supplying hydrogen atomscan include those gaseous or gasifiable materials, for example, hydrogengas (H₂), halides such as HF, HCl, HBr, and HI, silicon hydrides such asSiH₄, Si₂ H₆, Si₃ H₈, and Si₄ H₁₀, or halogen-substituted siliconhydrides such as SiH₂ F₂, SiH₂ I₂, SiH₂ Cl₂, SiHCl₃, SiH₂ Br₂, andSiHBr₃. The use of these gaseous starting material is advantageous sincethe content of the hydrogen atoms (H), which are extremely effective inview of the control for the electrical or photoelectronic properties,can be controlled with ease. Then, the use of the hydrogen halide or thehalogen-substituted silicon hydride as described above is particularlyadvantageous since the hydrogen atoms (H) are also introduced togetherwith the introduction of the halogen atoms.

The amount of the hydrogen atoms (H) and/or the amount of the halogenatoms (X) to be contained in a layer are adjusted properly bycontrolling related conditions, for example, the temperature of asubstrate, the amount of a gaseous starting material capable ofsupplying the hydrogen atoms or the halogen atoms into the depositionchamber and the electric discharging power.

In the case of forming a layer composed of A-Si(H,X) by the reactivesputtering process, the layer is formed on the substrate by using an Sitarget and sputtering the Si target in a plasma atmosphere.

To form said layer by the ion-plating process, the vapor of silicon isallowed to pass through a desired gas plasma atmosphere. The siliconvapor is produced by heating polycrystal silicon or single crystalsilicon held in a boat. The heating is accomplished by resistanceheating or electron beam method (E.B. method).

In either case where the sputtering process or the ion-plating processis employed, the layer may be incorporated with halogen atoms byintroducing one of the above-mentioned gaseous halides orhalogen-containing silicon compounds into the deposition chamber inwhich a plasma atmosphere of the gas is produced. In the case where thelayer is incorporated with hydrogen atoms in accordance with thesputtering process, a feed gas to liberate hydrogen is introduced intothe deposition chamber in which a plasma atmosphere of the gas isproduced. The feed gas to liberate hydrogen atoms includes H₂ gas andthe above-mentioned silanes.

For the formation of the layer in accordance with the glow dischargingprocess, reactive sputtering process or ion plating process, theforegoing halide or halogen-containing silicon compound can beeffectively used as the starting material for supplying halogen atoms.Other effective examples of said material can include hydrogen halidessuch as HF, HCl, HBr and HI and halogen-substituted silanes such as SiH₂F₂, SiH₂ I₂, SiH₂ Cl₂, SiHCl₃, SiH₂ Br₂ and SiHBr₃, which containhydrogen atom as the constituent element and which are in the gaseousstate or gasifiable substances. The use of the gaseous or gasifiablehydrogen-containing halides is particularly advantageous since, at thetime of forming a light receiving layer, the hydrogen atoms, which areextremely effective in view of controlling the electrical orphotoelectrographic properties, can be introduced into that layertogether with halogen atoms.

The structural introduction of hydrogen atoms into the layer can becarried out by introducing, in addition to these gaseous startingmaterials, H₂, or silicon hydrides such as SiH₄, SiH₆, Si₃ H₆, Si₄ H₁₀,etc. into the deposition chamber together with a gaseous or gasifiablesilicon-containing substance for supplying Si, and producing a plasmaatmosphere with these gases therein.

For example, in the case of the reactive sputtering process, the layercomposed of A-Si(H,X) is formed on the substrate by using an Si targetand by introducing a halogen atom introducing gas and H₂ gas, ifnecessary, together with an inert gas such as He or Ar into thedeposition chamber to thereby form a plasma atmosphere and thensputtering the Si target.

As for hydrogen atoms (H) and halogen atoms (X) to be optionallyincorporated in the layer, the amount of hydrogen atoms or halogenatoms, or the sum of the amount for hydrogen atoms and the amount forhalogen atoms (H+X) is preferably 1 to 40 atomic %, and, morepreferably, 5 to 30 atomic %.

The control of the amounts for hydrogen atoms (H) and halogen atoms (X)to be incorporated in the layer can be carried out by controlling thetemperature of a substrate, the amount of the starting material forsupplying hydrogen atoms and/or halogen atoms to be introduced into thedeposition chamber, discharging power, etc.

The formation of a layer composed of A-Si(H,X) containing germaniumatoms, oxygen atoms or/and nitrogen atoms, the group III atoms or thegroup V atoms in accordance with the glow discharging process, reactivesputtering process or ion plating process can be carried out by usingthe starting material for supplying germanium atoms, the startingmaterial for supplying oxygen atoms or/and nitrogen atoms, and thestarting material for supplying the group III or group V atoms togetherwith the starting materials for forming an A-Si(H,X) material and byincorporating relevant atoms in the layer to be formed while controllingtheir amounts properly.

To form the layer of a-SiGe(H,X) by the glow discharge process, a feedgas to liberate silicon atoms (Si), a feed gas to liberate germaniumatoms (Ge), and a feed gas to liberate hydrogen atoms (H) and/or halogenatoms (X) are introduced under appropriate gaseous pressure conditioninto an evacuatable deposition chamber, in which the glow discharge isgenerated so that a layer of a-SiGe(H,X) is formed on the properlypositioned substrate in the chamber.

The feed gases to supply silicon atoms, halogen atoms, and hydrogenatoms are the same as those used to form the layer of a-Si(H,X)mentioned above.

The feed gas to liberate Ge includes gaseous or gasifiable germaniumhalides such as GeH₄, Ge₂ H₆, Ge₃ H₈, Ge₄ H₁₀, Ge₅ H₁₂, Ge₆ H₁₄, Ge₇H₁₆, Ge₈ H₁₈, and Ge₉ H₂₀, with GeH₄, Ge₂ H₆ and Ge₃ H₈, beingpreferable on account of their ease of handling and the effectiveliberation of germanium atoms.

To form the layer of a-SiGe(H,X) by the sputtering process, two targets(a silicon target and a germaneium target) or a single target composedof silicon and germanium is subjected to sputtering in a desired gasatmosphere.

To form the layer of a-SiGe(H,X) by the ion-plating process, the vaporsof silicon and germanium are allowed to pass through a desired gasplasma atmosphere. The silicon vapor is produced by heating polycrystalsilicon or single crystal silicon held in a boat, and the germaniumvapor is produced by heating polycrystal germanium or single crystalgermanium held in a boat. The heating is accomplished by resistanceheating or electron beam method (E.B. method).

In either case where the sputtering process or the ion-plating processis employed, the layer may be incorporated with halogen atoms byintroducing one of the above-mentioned gaseous halides orhalogen-containing silicon compounds into the deposition chamber inwhich a plasma atmosphere of the gas is produced. In the case where thelayer is incorporated with hydrogen atoms, a feed gas to liberatehydrogen is introduced into the deposition chamber in which a plasmaatmosphere of the gas is produced. The feed gas may be gaseous hydrogen,silanes, and/or germanium hydrides. The feed gas to liberate halogenatoms includes the above-mentioned halogen-containing silicon compounds.Other examples of the feed gas include hydrogen halides such as HF, HCl,HBr, and HI; halogen-substituted silanes such as SiH₂ F₂, SiH₂ I₂, SiH₂Cl₂, SiHCl₃, SiH₂ Br₂, and SiHBr₃ ; germanium hydride halide such asGeHF₃, GeH₂ F₂, GeH₃ F, GeHCl₃, GeH₂ Cl₂, GeH₃ Cl, GeHBr₃, GeH₂ Br₂,GeH₃ Br, GeHI₃, GeH₂ I₂, and GeH₃ I; and germanium halides such as GeF₄,GeCl₄, GeBr₄, GeI₄, GeF₂, GeCl₂, GeBr₂, and GeI₂. They are in thegaseous form or gasifiable substances.

In order to form a layer or a partial layer region constituted withA-Si(H,X) further incorporated with oxygen atoms or/and nitrogen atomsand the group III atoms or the group V atoms (hereinafter referred to as"A-Si(H,X) (O,N) (M)" in which M stands for the group III atoms or thegroup V atoms) using the glow discharging process, reactive sputteringprocess or ion plating process, the starting materials for supplyingoxygen atoms or/and nitrogen atoms and for supplying the group III atomsor the group V atoms are used together with the starting materials forforming an A-Si(H,X) upon forming the layer or the partial layer regionwhile controlling their amounts to be incorporated therein.

Likewise, a layer or a partial layer region constituted with A-SiGe(O,N)(M) can be properly formed.

As the starting materials for supplying oxygen atoms, nitrogen atoms,the group III atoms and the group V atoms, most of gaseous or gasifiablematerials which contain at least such atoms as the constituent atoms canbe used.

In order to form a layer or a partial layer region containing oxygenatoms using the glow discharging process, starting material forintroducing the oxygen atoms is added to the material selected asrequired from the starting materials for forming said layer or partiallayer region as described above.

As the starting material for introducing oxygen atoms, most of thosegaseous or gasifiable materials which contain at least oxygen atoms asthe constituent atoms.

For instance, it is possible to use a mixture of a gaseous startingmaterial containing silicon atoms (Si) as the constituent atoms, agaseous starting material containing oxygen atoms (O) as the constituentatom and, as required, a gaseous starting material containing hydrogenatoms (H) and/or halogen atoms (X) as the constituent atoms in a desiredmixing ratio, a mixture of gaseous starting material containing siliconatoms (Si) as the constituent atoms and a gaseous starting materialcontaining oxygen atoms (O) and hydrogen atoms (H) as the constituentatoms in a desired mixing ratio, or a mixture of gaseous startingmaterial containing silicon atoms (Si) as the constituent atoms and agaseous starting material containing silicon atoms (Si), oxygen atoms(O) and hydrogen atoms (H) as the constituent atoms.

Further, it is also possible to use a mixture of a gaseous startingmaterial containing silicon atoms (Si) and hydrogen atoms (H) as theconstituent atoms and a gaseous starting material containing oxygenatoms (O) as the constituent atoms.

Specifically, there can be mentioned, for example, oxygen (O₂), ozone(O₃), nitrogen monoxide (NO), nitrogen dioxide (NO₂), dinitrogen oxide(N₂ O), dinitrogen trioxide (N₂ O₃), dinitrogen tetraoxide (N₂ O₄),dinitrogen pentoxide (N₂ O₅), nitrogen trioxide (NO₃), lower siloxanescomprising silicon atoms (Si), oxygen atoms (O) and hydrogen atoms (H)as the constituent atoms, for example, disiloxane (H₃ SiOSiH₃) andtrisiloxane (H₃ SiOSiH₂ OSiH₃), etc.

In the case of forming a layer or a partial layer region containingoxygen atoms by way of the sputtering process, it may be carried out bysputtering a single crystal or polycrystalline Si wafer or SiO₂ wafer,or a wafer containing Si and SiO₂ in admixture is used as a target andsputtered them in various gas atmospheres.

For instance, in the case of using the Si wafer as the target, a gaseousstarting material for introducing oxygen atoms and, optionally, hydrogenatoms and/or halogen atoms is diluted as required with a dilution gas,introduced into a sputtering deposition chamber, gas plasmas with thesegases are formed and the Si wafer is sputtered.

Alternatively, sputtering may be carried out in the atmosphere of adilution gas or in a gas atmosphere containing at least hydrogen atoms(H) and/or halogen atoms (X) as constituent atoms as a sputtering gas byusing individually Si and SiO₂ targets or a single Si and SiO₂ mixedtarget. As the gaseous starting material for introducing the oxygenatoms, the gaseous starting material for introducing the oxygen atomsshown in the examples for the glow discharging process as describedabove can be used as the effective gas also in the sputtering.

In order to form a layer or a partial layer region containing nitrogenatoms using the glow discharging process, the starting material forintroducing nitrogen atoms is added to the material selected as requiredfrom the starting materials for forming said layer or partial layerregion as described above. As the starting material for introducingnitrogen atoms, most of gaseous or gasifiable materials which contain atleast nitrogen atoms as the constituent atoms can be used.

For instance, it is possible to use a mixture of a gaseous startingmaterial containing silicon atoms (Si) as the constituent atoms, agaseous starting material containing nitrogen atoms (N) as theconstituent atoms and, optionally, a gaseous starting materialcontaining hydrogen atoms (H) and/or halogen atoms (X) as theconstituent atoms in a desired mixing ratio, or a mixture of a startinggaseous material containing silicon atoms (Si) as the constituent atomsand a gaseous starting material containing nitrogen atoms (N) andhydrogen atoms (H) as the constituent atoms also in a desired mixingratio.

Alternatively, it is also possible to use a mixture of a gaseousstarting material containing nitrogen atoms (N) as the constituent atomsand a gaseous starting material containing silicon atoms (Si) andhydrogen atoms (H) as the constituent atoms.

The starting material that can be used effectively as the gaseousstarting material for introducing the nitrogen atoms (N) used uponforming the layer or partial layer region containing nitrogen atoms caninclude gaseous or gasifiable nitrogen, nitrides and nitrogen compoundssuch as azide compounds comprising N as the constituent atoms or N and Has the constituent atoms, for example, nitrogen (N₂), ammonia (NH₃),hydrazine (H₂ NNH₂), hydrogen azide (HN₃) and ammonium azide (NH₄ N₃).In addition, nitrogen halide compounds such as nitrogen trifluoride (F₃N) and nitrogen tetrafluoride (F₄ N₂) can also be mentioned in that theycan also introduce halogen atoms (X) in addition to the introduction ofnitrogen atoms (N).

The layer or partial layer region containing nitrogen atoms may beformed through the sputtering process by using a single crystal orpolycrystalline Si wafer or Si₃ N₄ wafer or a wafer containing Si andSi₃ N₄ in admixture as a target and sputtering them in various gasatmospheres.

In the case of using an Si wafer as a target, for instance, a gaseousstarting material for introducing nitrogen atoms and, as required,hydrogen atoms and/or halogen atoms is diluted optionally with adilution gas, and introduced into a sputtering deposition chamber toform gas plasmas with these gases and the Si wafer is sputtered.

Alternatively, Si and Si₃ N₄ may be used as individual targets or as asingle target comprising Si and Si₃ N₄ in admixture and then sputteredin the atmosphere of a dilution gas or in a gaseous atmospherecontaining at least hydrogen atoms (H) and/or halogen atoms (X) as theconstituent atoms as for the sputtering gas. As the gaseous startingmaterial for introducing nitrogen atoms, those gaseous startingmaterials for introducing the nitrogen atoms described previously shownin the example of the glow discharging can be used as the effective gasalso in the case of the sputtering.

For instance, in the case of forming a layer or a partial layer regionconstituted with A-Si(H,X) (O,N) or A-SiGe(H,X) (O,N) furtherincorporated with the group III atoms or group V atoms by using the glowdischarging, sputtering, or ion-plating process, the starting materialfor introducing the group III or group V atoms are used together withthe starting materials for forming A-Si(H,X) (O,N) or A-SiGe(H,X) (O,N)upon forming the layer or partial layer region constituted withA-Si(H,X) (O,N) or A-SiGe(H,X) (O,N) as described above and they areincorporated while controlling their amounts.

Referring specifically to the boron atoms introducing materials as thestarting material for introducing the group III atoms, they can includeboron hydrides such as B₂ H₆, B₄ H₁₀, B₅ H₉, B₅ H₁₁, B₆ H₁₀, B₆ H₁₂, andB₆ H₁₄, and boron halides such as BF₃, BCl₃, and BBr₃. In addition,AlCl₃, CaCl₃, Ga(CH₃)₂, InCl₃, TlCl₃, and the like can also bementioned.

Referring to the starting material for introducing the group V atomsand, specifically, to the phosphorus atoms introducing materials, theycan include, for example, phosphorus hydrides such as PH₃ and P₂ H₆ andphosphorus halides such as PH₄ I, PF₃, PF₅, PCl₃, PCl₅, PBr₃, PBr₅, andPI₃. In addition, AsH₃, AsF₅, AsCl₃, AsBr₃, AsF₃, SbH₃, SbF₃, SbF₅,SbCl₃, SbCl₅, BiH₃, BiCl₃, and BiBr₃ can also be mentioned to as theeffective starting material for introducing the group V atoms.

Preparation of Second Layer (103)

The second layer 103 constituted with an amorphous material containingsilicon atoms as the main constituent atoms, carbon atoms, the group IIIatoms or the group V atoms, and optionally one or more kinds selectedfrom hydrogen atoms, halogen atoms, oxygen atoms and nitrogen atoms[hereinafter referred to as "A-SiCM(H,X) (O,N)" wherein M stands for thegroup III atoms or the group V atoms] can be formed in accordance withthe glow discharging process, reactive sputtering process or ion platingprocess by using appropriate starting materials for supplying relevantatoms together with the starting materials for forming an A-Si(H,X)material and incorporating relevant atoms in the layer to be formedwhile controlling their amounts properly.

For instance, in the case of forming the second layer in accordance withthe glow discharging process, the gaseous starting materials for formingA-SiCM(H,X) (O,N) are introduced into the deposition chamber having asubstrate, if necessary while, mixing with a dilution gas in apredetermined mixing ratio, the gaseous materials are exposed to a glowdischarging power energy to thereby generate gas plasmas resulting informing a layer to be the second layer 103 which is constituted withA-SiCM(H,X) (O,N) on the substrate.

In the typical embodiment, the second layer 103 is represented by alayer constituted with A-SiCM(H,X).

In the case of forming said layer, most of gaseous or gasifiablematerials which contain at least one kind selected from silicon atoms(Si), carbon atoms (C), hydrogen atoms (H) and/or halogen atoms (X), thegroup III atoms or the group V atoms as the constituent atoms can beused as the starting materials.

Specifically, in the case of using the glow discharging process forforming the layer constituted with A-SiCM(H,X), a mixture of a gaseousstarting material containing Si as the constituent atoms, a gaseousstarting material containing C as the constituent atoms, a gaseousstarting material containing the group III atoms or the group V atoms asthe constituent atoms and, optionally a gaseous starting materialcontaining H and/or X as the constituent atoms in a required mixingratio : a mixture of a gaseous starting material containing Si as theconstituent atoms, a gaseous material containing C, H and/or X as theconstituent atoms and a gaseous material containing the group III atomsor the group V atoms as the constituent atoms in a required mixing ratio: or a mixture of a gaseous material containing Si as the constituentatoms, a gaseous starting material containing Si, C and H or/and X asthe constituent atoms and a gaseous starting material containing thegroup III or the group V atoms as the constituent atoms in a requiredmixing ratio are optionally used.

Alternatively, a mixture of a gaseous starting material containing Si, Hand/or X as the constituent atoms, a gaseous starting materialcontaining C as the constituent atoms and a gaseous starting materialcontaining the group III atoms or the group V atoms as the constituentatoms in a required mixing ratio can be effectively used.

Those gaseous starting materials that are effectively usable herein caninclude gaseous silicon hydrides comprising C and H as the constituentatoms, such as silanes, for example, SiH₄, Si₂ H₆, Si₃ H₈ and Si₄ H₁₀,as well as those comprising C and H as the constituent atoms, forexample, saturated hydrocarbons of 1 to 4 carbon atoms, ethylenichydrocarbons of 2 to 4 carbon atoms and acetylenic hydrocarbons of 2 to3 carbon atoms.

Specifically, the saturated hydrocarbons can include methane (CH₄),ethane (C₂ H₆), propane (C₃ H₈), n-butane (n-C₄ H₁₀) and pentane (C₅H₁₂), the ethylenic hydrocarbons can include ethylene (C₂ H₄), propylene(C₃ H₆), butene-1 (C₄ H₈), butene-2 (C₄ H₈), isobutylene (C₄ H₈) andpentene (C₅ H₁₀) and the acetylenic hydrocarbons can include acetylene(C₂ H₂), methylacetylene (C₃ H₄) and butine (C₄ H₆).

The gaseous starting material comprising Si, C and H as the constituentatoms can include silicified alkyls, for example, Si(CH₃)₄ and Si(C₂H₅)₄. In addition to these gaseous starting materials, H₂ can of coursebe used as the gaseous starting material for introducing H.

For the starting materials for introducing the group III atoms, thegroup V atoms, oxygen atoms and nitrogen atoms, those mentioned above inthe case of forming the first layer can be used.

In the case of forming the layer constituted with A-SiCM(H,X) by way ofthe reactive sputtering process, it is carried out by using a singlecrystal or polycrystal Si wafer, a C (graphite) wafer or a wafercontaining a mixture of Si and C as a target and sputtering them in adesired gas atmosphere.

In the case of using, for example, a Si wafer as a target, gaseousstarting materials for introducing C, the group III atoms or the group Vatoms, and optionally H and/or X are introduced while being optionallydiluted with a dilution gas such as Ar and He into the sputteringdeposition chamber to thereby generate gas plasmas with these gases andsputter the Si wafer.

As the respective gaseous material for introducing the respective atoms,those mentioned above in the case of forming the first layer can beused.

As above explained, the first layer and the second layer to constitutethe light receiving layer of the light receiving member according tothis invention can be effectively formed by the glow discharging processor reactive sputtering process. The amount of germanium atoms; the groupIII atoms or the group V atoms; oxygen atoms or/and nitrogen atoms;carbon atoms; and hydrogen atoms or/and halogen atoms in the first layeror the second layer are properly controlled by regulating the gas flowrate of each of the starting materials or the gas flow ratio among thestarting materials respectively entering the deposition chamber.

The conditions upon forming the first layer or the second layer of thelight receiving member of the invention, for example, the temperature ofthe substrate, the gas pressure in the deposition chamber, and theelectric discharging power are important factors for obtaining the lightreceiving member having desired properties and they are properlyselected while considering the functions of the layer to be formed.Further, since these layer forming conditions may be varied depending onthe kind and the amount of each of the atoms contained in the firstlayer or the second layer, the conditions have to be determined alsotaking the kind or the amount of the atoms to be contained intoconsideration.

For instance, in the case of forming the layer constituted withA-Si(H,X) or the layer constituted with A-SiCM(H,X) (O,N), thetemperature of the support is preferably from 50° to to 350° C. and,more preferably, from 50° to 250° C.; the gas pressure in the depositionchamber is preferably from 0.01 to 1 Torr and, particularly preferably,from 0.1 to 0.5 Torr; and the electrical discharging power is usuallyfrom 0.005 to 50 W/cm², mor preferably, from 0.01 to 30 W/cm² and,particularly preferably, from 0.01 to 20 W/cm².

In the case of forming the layer constituted with A-SiGe(H,X) or thelayer constituted with A-SiGe(H,X) (O,N) (M), the temperature of thesupport is preferably from 50° to 350° C., more preferably, from 50° to300° C., most preferably 100° to 300° C.; the gas pressure in thedeposition chamber is usually from 0.01 to 5 Torr, more preferably, from0.01 to 3 Torr, most preferably from 0.1 to 1 Torr; and the electricaldischarging power is preferably from 0.005 to 50 W/cm², more preferably,from 0.01 to 30 W/cm², most preferably, from 0.01 to 20 W/cm².

However, the actual conditions for forming the first layer or the secondlayer such as temperature of the substrate, discharging power and thegas pressure in the deposition chamber cannot usually be determined withease independent of each other. Accordingly, the conditions optimal tothe layer formation are desirably determined based on relative andorganic relationships for forming the first layer and the second layerrespectively having desired properties.

By the way, it is necessary that the foregoing various conditions arekept constant upon forming the light receiving layer for unifying thedistribution state of germanium atoms, oxygen atoms or/and nitrogenatoms, carbon atoms, the group III atoms or group V atoms, or hydrogenatoms or/and halogen atoms to be contained in the first layer or thesecond layer according to this invention.

Further, in the case of forming the first layer containing, exceptsilicon atoms and optional hydrogen atoms or/and halogen atoms,germanium atoms and optional the group III atoms or the group V atomsand oxygen atoms or/and nitrogen atoms at a desirably distributed statein the thicknesswise direction of the layer by varying theirdistributing concentration in the thicknesswise direction of the layerupon forming the first layer in this invention, the layer is formed, forexample, in the case of the glow discharging process, by properlyvarying the gas flow rate of gaseous starting material for introducinggermanium atoms, the group III atoms or the group V atoms, and oxygenatoms or/and nitrogen atoms upon introducing into the deposition chamberin accordance with a desired variation coefficient while maintainingother conditions constant. Then, the gas flow rate may be varied,specifically, by gradually changing the opening degree of apredetermined needle valve disposed to the midway of the gas flowsystem, for example, manually or any of other means usually employedsuch as in externally driving motor. In this case, the variation of theflow rate may not necessarily be linear but a desired content curve maybe obtained, for example, by controlling the flow rate along with apreviously designed variation coefficient curve by using a microcomputeror the like.

Further, in the case of forming the first layer in accordance with thereactive sputtering process, a desirably distributed state of germaniumatoms, the group III atoms or the group V atoms, and oxygen atoms or/andnitrogen atoms in the thicknesswise direction of the layer may beestablished with the distributing concentration being varied in thethicknesswise direction of the layer by using a relevant startingmaterial for introducing germanium atoms, the group III or group Vatoms, and oxygen atoms or/and nitrogen atoms and varying the gas flowrate upon introducing these gases into the deposition chamber inaccordance with a desired variation coefficient in the same manner asthe case of using the glow discharging process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described more specifically while referring toExamples 1 through 74, but he invention is not intended to limite thescope only to these Examples.

In each of the Examples, the first layer and the second layer wereformed by using the glow discharging process.

FIG. 14 shows an apparatus for preparing a light receiving memberaccording to this invention by means of the glow discharging process.

Gas reservoirs 1402, 1403, 1404, 1405, and 1406 illustrated in thefigure are charged with gaseous starting materials for forming therespective layers in this invention, that is, for instance, SiH₄ gas(99.999% purity) diluted with He (hereinafter referred to as "SiH₄ /He")in gas reservoir 1402, B₂ H₆ gas (99.999% purity) diluted with He(hereinafter referred to as "B₂ H₆ /He") in gas reservoir 1403, NH₃ gas(99.999% purity) diluted with He (hereinafter referred to as "NH₃ /He")in gas reservoir 1404, C₂ H₄ gas (99.999% purity) in gas reservoir 1405,and GeH₄ gas (99.999% purity) diluted with He (hereinafter referred toas "GeH₄ /He") in gas reservoir 1406.

In the case of incorporating halogen atoms in the layer to be formed,for example, SiF₄ gas in another gas reservoir is used in stead of theforegoing SiH₄ gas.

Prior to the entrance of these gases into a reaction chamber 1401, it isconfirmed that valves 1422 through 1426 for the gas reservoirs 1402through 1406 and a leak valve 1435 are closed and that inlet valves 1412through 1416, exit valves 1417 through 1421, and sub-valves 1432 and1433 are opened. Then, a main valve 1434 is at first opened to evacuatethe inside of the reaction chamber 1401 and gas piping.

Then, upon observing that the reading on the vacuum 1436 became about5×10⁻⁶ Torr, the sub-valves 1432 and 1433 and the exit valves 1417through 1421 are closed.

Now, reference is made in the following to an example in the case offorming a layer to be the first layer 102 on an Al cylinder as thesubstrate 1437.

At first, SiH₄ /He gas from the gas reservoir 1402, B₂ H₆ /He gas fromthe gas reservoir 1403, NH₃ /He gas from the gas reservoir 1404, andGeH₄ /He gas from the gas reservoir 1406 are caused to flow into massflow controllers 1407, 1408, 1409, and 1411 respectively by opening theinlet valves 1412, 1413, 1414, and 1416, controlling the pressure ofexit pressure gauges 1427, 1428, 1429, and 1431 to 1 kg/cm².Subsequently, the exit valves 1417, 1418, 1419, and 1421, and thesub-valves 1432 and 1433 are gradually opened to enter the gases intothe reaction chamber 1401. In this case, the exit valves 1417, 1418,1419, and 1421 are adjusted so as to attain a desired value for theratio maong the SiH₄ /He gas flow rate, B₂ H₆ /He gas flow rate, NH₃ /Hegas flow rate, and Ga/He gas flow rate, and the opening of the mainvalve 1434 is adjusted while observing the reading on the vacuum gauge1436 so as to obtain a desired value for the pressure inside thereaction chamber 1401. Then, after confirming that the temperature ofthe Al cylinder substrate 1437 has been set by heater 1438 within arange from 50° to 350° C., a power source 1440 is set to a predeterminedelectrical power to cause glow discharging in the reaction chamber 1401while controlling the flow rates for GeH₄ /He gas, B₂ H₆ /He gas, NH₃/He gas and SiH₄ gas in accordance with a previously designed variationcoefficient curve by using a microcomputer (not shown), thereby forming,at first, a layer of an amorphous silicon material to be the first layer102 containing germanium atoms, boron atoms and nitrogen atoms on the Alcylinder.

Then, a layer to be the second layer 103 is formed on the photosensitivelayer. Subsequent to the procedures as described above, SiH₄ gas, C₂ H₄gas and PH₃ gas, for instance, are optionally diluted with a dilutiongas such as He, Ar and H₂ respectively, entered at a desired gas flowrates into the reaction chamber 1401 while controlling the gas flowrates for the SiH₄ gas, the C₂ H₄ gas and the PH₃ gas by using amicrocomputer and glow discharge being caused in accordance withpredetermined conditions, by which the second layer constituted withA-SiCM(H,X) is formed.

All of the exit valves other than those required for upon forming therespective layers are of course closed. Further, upon forming therespective layers, the inside of the system is once evacuated to a highvacuum degree as required by closing the exit valves 1417 through 1421while opening the sub-valves 1432 and 1433 and fully opening the mainvalve 1434 for avoiding that the gases having been used for forming theprevious layer are left in the reaction chamber 1401 and in the gaspipeways from the exit valves 1417 through 1421 to the inside of thereaction chamber 1401.

Further, during the layer forming operation, the Al cylinder assubstrate 1437 is rotated at a predetermined speed by the action of themotor 1439.

EXAMPLE 1

A light receiving layer was formed on a cleaned Al cylinder under thelayer forming conditions shown in Table 1 using the fabricationapparatus shown in FIG. 14 to obtain a light receiving member for use inelectrophotography. Wherein, the change in the gas flow ratio of GeH₄/SiH₄ was controlled automatically using a microcomputer in accordancewith the flow ratio curve shown in FIG. 15. The resulting lightreceiving member was set to an electrophotographic copying machinehaving been modified for experimental purposes, and subjected to copyingtests using a test chart provided by Canon Kabushiki Kaisha of Japanunder selected image forming conditions. As the light source, tungstenlamp was used.

As a result, there were obtained high quality visible images with animproved resolving power.

EXAMPLES 2 to 7

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 2 to 7respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄ and the gas flowratio for B₂ H₆ /SiH₄ were controlled in accordance with the flow ratiocurve shown in the following Table A.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE A                                                         ______________________________________                                                 Number of the Figure                                                                          Number of the Figure                                 Example  for the gas flow ratio                                                                        for the flow ratio of                                No.      curve for GeH.sub.4 /SiH.sub.4                                                                B.sub.2 H.sub.6 /SiH.sub.4                           ______________________________________                                        2        16              --                                                   3        17              --                                                   4        17              --                                                   5        15              18                                                   6        16              19                                                   7        17              20                                                   ______________________________________                                    

EXAMPLE 8

Light receiving members (Sample Nos. 801 to 807) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the layer thickness was changed as shown in Table 8 in thecase of forming the second layer in the Table 1.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 8.

EXAMPLE 9

Light receiving members (Sample Nos. 901 to 907) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the value relative to the flow ratio for C₂ H₄ /SiH₄ in thecase of forming the second layer in Table 1 was changed as shown inTable 9.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLES 10 to 18

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Table 10 to 18respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄, the gas flow ratiofor B₂ H₆ /SiH₄ and the gas flow ratio for O₂ /SiH₄ were controlled inaccordance with the flow ratio curve shown in the following Table B.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE B                                                         ______________________________________                                                Number of the                                                                             Number of the Number of the                                       Figure for the                                                                            Figure for the                                                                              Figure for the                                      gas flow ratio                                                                            gas flow ratio                                                                              gas flow ratio                              Example curve for   curve for     curve for                                   No.     GeH.sub.4 /SiH.sub.4                                                                      B.sub.2 H.sub.6 /SiH.sub.4                                                                  O.sub.2 /SiH.sub.4                          ______________________________________                                        10      15          --            --                                          11      16          --            22                                          12      17          --            23                                          13      16          --            24                                          14      16          --            --                                          15      15          18            --                                          16      17          19            22                                          17      17          --            --                                          18      15          20            22                                          ______________________________________                                    

EXAMPLE 19

Light receiving members (Sample Nos. 1901 to 1907) for use inelectrophotography were prepared by almost the same procedures as inExample 1, except that the layer thickness was changed as shown in Table19 in the case of forming the second layer in Table 10.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 19.

EXAMPLE 20

Light receiving members (Sample Nos. 2001 to 2007) for use inelectrophotography were prepared by almost the same procedures as inExample 1, except that the value relative to the flow ratio for C₂ H₄/SiH₄ in the case of forming the second layer in Table 10 was changed asshown in Table 20.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLES 21 to 30

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 21 to 30respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄, the gas flow ratiofor B₂ H₆ /SiH₄ and the gas flow ratio for NH₃ /SiH₄ were controlled inaccordance with the flow ratio curve shown in the following Table C.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE C                                                         ______________________________________                                                Number of the                                                                             Number of the Number of the                                       Figure for the                                                                            Figure for the                                                                              Figure for the                                      gas flow ratio                                                                            gas flow ratio                                                                              gas flow ratio                              Example curve for   curve for     curve for                                   No.     GeH.sub.4 /SiH.sub.4                                                                      B.sub.2 H.sub.6 /SiH.sub.4                                                                  NH.sub.3 /SiH.sub.4                         ______________________________________                                        21      15          --            --                                          22      16          --            22                                          23      17          --            23                                          24      16          --            24                                          25      16          --            --                                          26      15          18            --                                          27      17          19            22                                          28      17          21            --                                          29      15          20            22                                          30      16          --            --                                          ______________________________________                                    

EXAMPLE 31

Light receiving members (Sample Nos. 3101 to 3107) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the layer thickness was changed as shown in Table 31 in thecase of forming the second layer in Table 21.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 31.

EXAMPLE 32

Light receiving members (Sample Nos. 3201 to 3207) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the value relative to the flow ratio for C₂ H₄ /SiH₄ in thecase of forming the second layer in Table 21 was changed as shown inTable 32.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLES 33 to 35

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 33 to 35respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄ was controlled inaccordance with the flow ratio curves shown in FIGS. 25 to 27.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

EXAMPLES 36 to 42

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 36 to 42respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄ and the gas flowratio for B₂ H₆ /SiH₄ were controlled in accordance with the flow ratecurve shown in the following Table D.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE D                                                         ______________________________________                                                 Number of the Figure                                                                          Number of the Figure                                 Example  for the gas flow ratio                                                                        for the gas flow ratio                               No.      curve for GeH.sub.4 /SiH.sub.4                                                                curve for B.sub.2 H.sub.4 /SiH.sub.4                 ______________________________________                                        36       25              --                                                   37       26              --                                                   38       27              --                                                   39       27              --                                                   40       25              18                                                   41       25              19                                                   42       26              20                                                   ______________________________________                                    

EXAMPLE 43

Light receiving members (Sample Nos. 4301 to 4307) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the layer thickness was changed as shown in Table 43 in thecase of forming the second layer in Table 36.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 43.

EXAMPLE 44

Light receiving members (Sample Nos. 4401 to 4407) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the value relative to the flow ratio for C₂ H₄ /SiH₄ in thecase of forming the second layer in Table 36 was changed as shown inTable 44.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLES 45 to 52

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 45 to 52respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄, the gas flow ratiofor B₂ H₆ /SiH₄ and the gas flow ratio for O₂ /SiH₄ were controlled inaccordance with the flow ratio curve shown in the following Table E.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE E                                                         ______________________________________                                                Number of the                                                                             Number of the                                                                             Number of the                                         Figure for the                                                                            Figure for the                                                                            Figure for the                                        gas flow ratio                                                                            gas flow ratio                                                                            gas flow ratio                                Example curve for   curve for   curve for                                     No.     GeH.sub.4 /SiH.sub.4                                                                      B.sub.2 H.sub.6 /SiH.sub.4                                                                O.sub.2 /SiH.sub.4                            ______________________________________                                        45      25          --          --                                            46      26          --          22                                            47      25          --          23                                            48      27          --          24                                            49      25          --          --                                            50      25          18          --                                            51      26          19          22                                            52      25          20          22                                            ______________________________________                                    

EXAMPLE 53

Light receiving members (Sample Nos. 5301 to 5307) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the layer thickness was changed as shown in Table 53 in thecase of forming the second layer in Table 45.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 53.

EXAMPLE 54

Light receiving members (Sample Nos. 5401 to 5407) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the value relative to the flow ratio for C₂ H₄ /SiH₄ in thecase of forming the second layer in Table 45 was changed as shown inTable 54.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLES 55 to 63

In each example, the same procedures as in Example 1 were repeated,except using the layer forming conditions shown in Tables 55 to 63respectively, to thereby obtain a light receiving member in drum formfor use in electrophotography.

In each example, the gas flow ratio for GeH₄ /SiH₄, the gas flow ratiofor B₂ H₆ /SiH₄ and the gas flow ratio for NH₃ /SiH₄ were controlled inaccordance with the flow ratio curve shown in the following Table F.

The resulting light receiving members were subjected to the same copyingtest as in Example 1.

As a result, there were obtained high quality and highly resolvedvisible images for any of the light receiving members.

                  TABLE F                                                         ______________________________________                                                Number of the                                                                             Number of the                                                                             Number of the                                         Figure for the                                                                            Figure for the                                                                            Figure for the                                        gas flow ratio                                                                            gas flow ratio                                                                            gas flow ratio                                Example curve for   curve for   curve for                                     No.     GeH.sub.4 /SiH.sub.4                                                                      B.sub.2 H.sub.6 /SiH.sub.4                                                                NH.sub.3 /SiH.sub.4                           ______________________________________                                        55      25          --          --                                            56      26          --          22                                            57      25          --          23                                            58      27          --          24                                            59      25          --          --                                            60      25          18          --                                            61      26          19          22                                            62      25          20          22                                            63      26          --          --                                            ______________________________________                                    

EXAMPLE 64

Light receiving members (Sample Nos. 6401 to 6407) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the layer thickness was changed as shown in Table 64 in thecase of forming the second layer in Table 55.

The resulting light receiving members were respectively evaluated inaccordance with the same image forming process as in Example 1.

The results were as shown in Table 64.

EXAMPLE 65

Light receiving members (Sample Nos. 6501 to 6507) for use inelectrophotography were prepared by the same procedures as in Example 1,except that the value relative to the flow ratio for C₂ H₄ /SiH₄ in thecase of forming the second layer in Table 55 was changed as shown inTable 65.

The resulting light receiving members were respectively evaluated inaccordance with the same procedures as in Example 1.

As a result, it was confirmed for each of the samples that high qualityvisible images with clearer half tone could be repeatedly obtained.

And, in the durability test upon repeating use, it was confirmed thatany of the samples has an excellent durability and always brings abouthigh quality visible images equivalent to initial visible images.

EXAMPLE 66

In Examples 33 through 65, except that there were practiced formation ofelectrostatic latent images and reversal development using GaAs seriessemiconductor laser (10 mW) in stead of the tungsten lamp as the lightsource, the same image forming process as in Example 1 was employed foreach of the light receiving members and the resulting transferred tonorimages evaluated.

As a result, it was confirmed that any of the light receiving membersalways brings about high quality and highly resolved visible images withclearer half tone.

                                      TABLE 1                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.19  8.5   4                             layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1 → 1/2                          GeH.sub.4 /He = 1                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 0                                                     0.19  17    14                                step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/30000                                               __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.19  8.5   4                             layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1 → 1/6                          GeH.sub.4 /He = 1                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                     0.19  17    16                                step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1.5                           layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.19  8.5   1                             layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1                                       GeH.sub.4 /He = 1                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4                                                                0.19  8.5   19                                step B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1/100                                   GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1.5                           layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4 ) =              B.sub.2 H.sub.6 /He = 1/100                                                                  1/3000                                                __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1                                                                  0.19  8.5   1                             layer                                                                             step GeH.sub.4 /He = 1                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                              0.20  18    18                                step GeH.sub.4 /He = 1                                                        Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                              0.16  12    1                                 step B.sub.2 H.sub.6 /He = 1/100                                                                  B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                           GeH.sub.4 /He = 1                                                    Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/10000                                               __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 =                                                              0.19  8.5   4                             layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  5/10000 → 0                                             GeH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1 → 1/2                     Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 0                                                     0.19  17    14                                step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 6                                     __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000 →                                               0.19  8.5   16                           layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 =                                         GeH.sub.4 /He = 1                                                                            1 → 1/6 → (A)                               Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = (A) → 0                                                      0.19  17    4                                step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     1.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub. 3 /He = 1/100                                                                        1/30000                                               __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 =                                                              0.18  8.5   3                             layer                                                                             step B.sub.2 H.sub.6 /He = 1/100                                                                  = 4/4000 →0                                             GeH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1                                  Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /He = 1 →1/100                                                           0.19  17    15                                step GeH.sub.4 /He = 1                                                        Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                                                      0.18  16    2                                 step B.sub.2 H.sub.6 /He = 1/100                                                                  = 0→1/4000                                              GeH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/100                          Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                 B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/4000                                              __________________________________________________________________________

                  TABLE 8                                                         ______________________________________                                        Sample No. 801     802    803  804  805  806  807                             ______________________________________                                        Thickness of                                                                             0.1     0.5    1.5  2    3    4    5                               the second layer                                                              (μ)                                                                        Evaluation Δ ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                           ○                                                                           Δ                         ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                  TABLE 9                                                         ______________________________________                                        Sample No.                                                                            901     902    903   904  905   906  907                              ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                            1/10    2/10   4/10  5/10 10/10 2/1  3/1                              Flow ratio                                                                    Evaluation                                                                            ○                                                                              ⊚                                                                     ⊚                                                                    ○                                                                           ○                                                                            ○                                                                           Δ                          ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                                      TABLE 10                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 →1/2                                                     0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                            B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 →0                                                       0.26  18    14                               step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(C.sub.2 H.sub.4 + SiH.sub.4 )                       PH.sub.3 /He = 1/100                                                                         = 1/30000                                             __________________________________________________________________________

                                      TABLE 11                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 →1/6                                                    0.18  8     4                             layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                          B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 →0                                                      0.20  18    16                                step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                          B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 =  3/10                                                        0.16  5     0.5                           layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                        PH.sub.3 /He = 1/100                                                                         = 1/30000                                             __________________________________________________________________________

                                      TABLE 12                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1                                                                           1                              layer                                                                             step                O.sub.2 /SiH.sub.4 = 5/1000                                                   → 3.75/1000                                             GeH.sub.4 /He = 1         0.18  8                                        Second                                                                             O.sub.2 /He = 0.5                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                                         3                                  step                O.sub.2 /SiH.sub.4 = 3.75/1000                                                → 0                                                Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                             0.20  18    15                                 step GeH.sub.4 /He = 1                                                        Forth                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4  = 1/100                                                            0.14  12    1                                  step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                           B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Fifth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     0.5                            layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                 B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/10000                                             __________________________________________________________________________

                                      TABLE 13                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /He = 1 → 1/6                                                           0.16  7     8                              layer                                                                             step GeH.sub.4 /He = 1                                                                            → 3/24                                                  B.sub.2 H.sub.6 /He = 1/100                                                                  B.sub.2 H.sub.6 /He = 1/1000                                   O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 4/40000                                                  → 0.25/40000                                       Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /He = 3/24 → 0                                                          0.18  8     16                                 step GeH.sub.4 /He = 1                                                                            O.sub.2 /SiH.sub.4 = 0.25/40000                                O.sub.2 /He = 0.5                                                                            → 1.5/40000                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     0.5                            layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                 B.sub.2 H.sub.6 /He = 1/100                                                                  = 1.5/40000                                           __________________________________________________________________________

                                      TABLE 14                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                        0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/2 → 1/6                        B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                      0.20  11    16                               step GeH.sub.4 /He = 1                                                                            O.sub.2 /SiH.sub.4 = 1/400                                     O.sub.2 /He = 0.5                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  4     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                        PH.sub.3 /He = 1/100                                                                         = 1/30000                                                      O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 1/400                            __________________________________________________________________________

                                      TABLE 15                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 1/2                                                    0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4                                     B.sub.2 H.sub.6 /He = 1/100                                                                  = 5/1000 → 0                                            O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 1/40                                 Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 0                                                      0.20  11    16                               step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     (O.sub.2 + C.sub.2 H.sub.4)/SiH.sub.4                                                      0.17  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              = 3/10                                                         PH.sub. 3 /He = 1/100                                                                        PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4 + O.sub.2)              O.sub.2 /He = 0.5                                                                            = 1/30000                                             __________________________________________________________________________

                                      TABLE 16                                    __________________________________________________________________________    Layer                                                                             Layer          Flow              Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas       amount                                                                             Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used      (SCCM)                                                                             ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                       SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1                                                                0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                             →1/100                                                 B.sub.2 H.sub.6 /He = 1/100                                                                   B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                           O.sub.2 /He = 0.5                                                                             →3.75/1000                                                             O.sub.2 /SiH.sub.4 = 1/40→0                       Second                                                                             SiH.sub.4 /He = 1                                                                       SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                              0.20  18    16                               step GeH.sub.4 /He = 1                                                                             B.sub.2 H.sub.6 /SiH.sub.4                                    B.sub.2 H.sub.6 /He = 1/100                                                                   = 3.75/1000 →0                                Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                     SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4 PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                       PH.sub.3 /He = 1/100                                                                          = 1/30000                                            __________________________________________________________________________

                                      TABLE 17                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1                                                                           1                              layer                                                                             step                O.sub.2 /SiH.sub.4 = 1/50                                      GeH.sub.4 /He = 1         0.18  8                                        Second                                                                             O.sub.2 /He = 0.5                                                                            GeH.sub.4 /SiH.sub.4 = 1/100                                                                         1                                  step                O.sub.2 /SiH.sub.4 = 1/50                                 Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                             0.20  18    17                                 step GeH.sub.4 /He = 1                                                        Forth                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 0                                                           0.14  12    1                                  step GeH.sub.4 /He = 1                                                                            → 1/10000                                               B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1/100                          Second                                                                            Fifth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     1                              layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                 B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/10000                                             __________________________________________________________________________

                                      TABLE 18                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2                                                                 0.18  9     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            →1/6                                                    B.sub.2 H.sub.6 /He = 1/100                                                                  B.sub.2 H.sub.6 /SiH.sub.4 = 4/4000→0                   O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 1/40→0                        Second                                                                             SiH.sub.4 = 1                                                                          SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 →0                                                       0.26  0.18  16                               step GeH.sub.4 = 1  B.sub.2 H.sub.6 /SiH.sub.4 = 0                                 B.sub.2 H.sub.6 /He = 1/100                                                                  →1/4000                                        Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                 B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/4000                                              __________________________________________________________________________

                  TABLE 19                                                        ______________________________________                                        Sample No.  1901   1902   1903 1904 1905 1906 1907                            ______________________________________                                        Thickness of                                                                              0.1    0.5    1.5  2    3    4    5                               the second layer                                                              (μ)                                                                        Evaluation  Δ                                                                              ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                           ○                                                                           Δ                         ______________________________________                                         ⊚: Excellent                                                    ○ : Good                                                              Δ: Applicable for practical use                                    

                  TABLE 20                                                        ______________________________________                                        Sample No.                                                                             2001   2002    2003 2004  2005 2006  2007                            ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                             1/10   2/10    4/10 5/10  10/10                                                                              2/1   3/1                             Flow ratio                                                                    Evaluation                                                                             ○                                                                             ⊚                                                                      ⊚                                                                   ○                                                                            ○                                                                           ○                                                                            Δ                         ______________________________________                                         ⊚: Excellent                                                    ○ : Good                                                              Δ: Applicable for practical use                                    

                                      TABLE 21                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 1/2                                                    0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                            B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40                                     NH.sub.3 /He = 0.5                                                       Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 0                                                      0.20  18    14                               step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(C.sub.2 H.sub.4  + SiH.sub.4) =                     PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 22                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 →                                                        0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            1/2                                                            B.sub.2 H.sub.6 /He = 1/100                                                                  B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                          NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/40                                Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                      0.20  18    16                               step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                          B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 =  3/10                                                         0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 23                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1                                                                 0.18  8     1                            layer                                                                             step GeH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 5/1000 →                     Second                                                                             NH.sub.3 /He = 0.5                                                                           3.75/1000                                                 step                GeH.sub.4 /SiH.sub.4 = 1/100                                                                           3                                                    NH.sub.3 /SiH.sub.4 → 3.75/1000 →                               0                                                         Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                               0.20  18    15                               step GeH.sub.4 /He = 1                                                        Forth                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                               0.14  12    1                                step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                           B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Fifth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/10000                                               __________________________________________________________________________

                                      TABLE 24                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /He = 1 →                                                                 0.16  7     8                            layer                                                                             step GeH.sub.4 /He = 1                                                                            1/6 → 3/24                                              B.sub.2 H.sub.6 /He = 1/100                                                            B.sub.2 H.sub.6 /He = 1/1000                                         NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 4/40000 →                                        0.25/40000                                                Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /He = 3/24 → 0                                                            0.18  8     16                               step GeH.sub.4 /He = 0.5                                                                          NH.sub.3 /SiH.sub.4 =                                          NH.sub.3 /He = 0.5                                                                           0.25/40000 → 1.5/40000                         Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1.5/40000                                             __________________________________________________________________________

                                      TABLE 25                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                        0.18  8     4                            layer                                                                             step GeH.sub.4 He = 1                                                                             GeH.sub.4 SiH.sub.4 = 1/2 →                             B.sub.2 H.sub.6 /He = 1/100                                                                  1/6                                                            NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/40                                Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                      0.20  11    16                               step GeH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 1/400                                    NH.sub.3 /He = 0.5                                                   Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 =  3/10                                                         0.16  4     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                                        NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/400                           __________________________________________________________________________

                                      TABLE 26                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 1/2                                                    0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000 →                   B.sub.2 H.sub.6 /He = 1/100                                                                  0                                                              NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/40                                Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 0                                                      0.20  11    16                               step GeH.sub.4 /He = 1                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     (NH.sub.3 + C.sub.2 H.sub.4)/SiH.sub. 4                                                    50.17 0.5                                layer                                                                             step C.sub.2 H.sub.4                                                                              3/10                                                           PH.sub.3 /He = 1/100                                                                         PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4 +                       NH.sub.3 /He = 0.5                                                                           NH.sub.3) = 1/3000                                    __________________________________________________________________________

                                      TABLE 27                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 →                                                        0.18  8     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            1/100                                                          B.sub.2 H.sub.6 /He = 1/100                                                                  B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000 →                   NH.sub.3 /He = 0.5                                                                           3.75/1000                                                                     NH.sub.3 /SiH.sub.4 = 1/40 → 0                     Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                               0.20  18    16                               step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 3.75/1000 →                B.sub.2 H.sub.6 /He = 1/100                                                                  0                                                     Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 28                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1                                                                 0.18  8     1                            layer                                                                             step GeH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 1/50                                Second                                                                             O.sub.2 /He = 0.5                                                                            GeH.sub.4 /SiH.sub.4 = 1/100                                                                           1                                step                NH.sub.3 /SiH.sub.4 = 1/50                                Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/100                                                               0.20  18    17                               step GeH.sub.4 /He = 1                                                        Forth                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 0 →                                                    0.14  12    1                                step GeH.sub.4 /He = 1                                                                            1/10000                                                        B.sub.2 H.sub.6 /He = 1/100                                                                  GeH.sub.4 /SiH.sub.4 = 1/100                          Second                                                                            Fifth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     1                            layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 (SiH.sub.4 + C.sub.2 H.sub.4)=                 B.sub.2 H.sub.6 /He = 1/100                                                                  1/10000                                               __________________________________________________________________________

                                      TABLE 29                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 1/6                                                    0.18  9     4                            layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 4/4000 → 0                 B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40 → 0                          NH.sub.3 /He = 0.5                                                       Second                                                                             SiH.sub.4 = 1                                                                          SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                      0.20  0.18  16                               step GeH.sub.4 = 1  B.sub.2 H.sub.6 /SiH.sub.4 = 0 →                        B.sub.2 H.sub.6 /He = 1/100                                                                  1/4000                                                Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/4000                                                __________________________________________________________________________

                                      TABLE 30                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/2 → 1/3                                                    0.20  8     2                            layer                                                                             step GeH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 1/50                                     NH.sub.3       O.sub.2 /SiH.sub.4 = 1/200                                Second                                                                             O.sub.2 /He = 0.5                                                                            GeH.sub.4 /SiH.sub.4 = 1/3 → 1/6                                                    0.20  17.5  2                                step                NH.sub.3 /SiH.sub.4 = 1/100                                                   O.sub.2 /SiH.sub.4 = 1/1000                               Third                                                                              SiH.sub.4 He = 1                                                                       SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/6 → 0                                                      0.15  12.5  16                               step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                           B.sub.2 H.sub.6 /He =  1/100                                         Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                          0.16  5     0.5                          layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sup.4 ) =              B.sub.2 H.sub.6 /He = 1/100                                                                  1/10000                                               __________________________________________________________________________

                  TABLE 31                                                        ______________________________________                                        Sample No.  3101   3102   3103 3104 3105 3106 3107                            ______________________________________                                        Thickness of                                                                  the second layer                                                                          0.1    0.5    1.5  2    3    4    5                               (μ)                                                                        Evaluation  Δ                                                                              ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                           ○                                                                           Δ                         ______________________________________                                         ⊚: Excellent                                                    ○ : Good                                                              Δ: Applicable for practical use                                    

                  TABLE 32                                                        ______________________________________                                        Sample No.                                                                            3201    3202   3203  3204 3205  3206 3207                             ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                    Flow ratio                                                                            1/10    2/10   4/10  5/10 10/10 2/1  3/1                              Evaluation                                                                            ○                                                                              ⊚                                                                     ⊚                                                                    ○                                                                           ○                                                                            ○                                                                           Δ                          ______________________________________                                         ⊚: Excellent                                                    ○  : Good                                                             Δ: Applicable for practical use                                    

                                      TABLE 33                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     GeH.sub.4 SiH.sub.4 = 1/1 → 0                                                      0.18  9     4                             First                                                                             step GeH.sub.4 /He = 0.5                                                  layer                                                                             Second                                                                             SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200   0.20  18    16                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     SiH.sub.4 /C.sub.2 H.sub.4 = 1/1                                                          0.18  6     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 (SiH.sub.4 + C.sub.2 H.sub.4) =                B.sub.2 H.sub.6 /He = 0.01                                                                   5/100000                                              __________________________________________________________________________

                                      TABLE 34                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                                                     0.20  11    2                             First                                                                             step GeH.sub.4 /He = 0.5                                                  layer                                                                             Second                                                                             SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200   0.20  18    18                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     SiH.sub.4 /C.sub.2 H.sub.4 = 1/1                                                          0.18  6     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 (SiH.sub.4 + C.sub.2 H.sub.4) =                B.sub.2 H.sub.6 /He = 0.01                                                                   5/100000                                              __________________________________________________________________________

                                      TABLE 35                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________        First               GeH.sub.4 /SiH.sub.4 = 1/1                                                               0.18  9     1                                  step SiH.sub.4 /He = 0.5                                                  First                                                                             Second                                                                             GeH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/3                                                               0.19  10    6                              layer                                                                             step                                                                          Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200  0.20  18    13                                 step                                                                      Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     SiH.sub.4 /C.sub.2 H.sub.4 = 1/1                                                         0.18  6     1                              layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + GeH.sub.4) =                     B.sub.2 H.sub.6 He = 0.01                                                                    5/100000                                              __________________________________________________________________________

                                      TABLE 36                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                                                     0.19  8     4                                 step GeHe/He = 1    B.sub.2 H.sub.6 SiH.sub.4 = 5/1000                    First    B.sub.2 H.sub.6 He = 1/100                                           layer                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    16                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 He = 0.5                                                                     SiH.sub.4 200                                                                       C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 37                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 1 → 0                                                         0.19  8     2                                 step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                 First    B.sub.2 H.sub.6 /He = 1/100                                          layer                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                                                     0.20  18    14                                step B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1.5                           layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 38                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1                                                                 0.18  10    1                                  First                                                                              GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/100                    First                                                                             step B.sub.2 H.sub.6 /He = 1/100                                          layer                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/30.18                                                           10    6                                        step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/1000                            B.sub.2 H.sub.6 /He = 1/100                                              Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200  0.20  18    10                                 step                                                                      Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     1.5                            layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/3000                                                __________________________________________________________________________

                                      TABLE 39                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________        First         SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1                                                                 0.19  17    1                                  step SiH.sub.4 /He = 1                                                        Second                                                                             GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/3                                                               0.19  17    6                              First                                                                             step                                                                      layer                                                                             Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200  0.20  18    12                                 step                                                                          Forth                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                                                     0.14  12    1                                  step B.sub.2 H.sub.6 /He = 1/100                                          Second                                                                            Fifth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     1                              layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sup.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/10000                                               __________________________________________________________________________

                                      TABLE 40                                    __________________________________________________________________________    Layer                                                                             Layer         Flow             Discharg-                                                                           Deposition                                                                          Layer                          consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow       ing power                                                                           speed thickness                      tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio      (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                         __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1 → 0                                                      0.19  17    4                                  step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                   First    B.sub.2 H.sub.6 /He = 1/100                                                                  → 0                                            layer                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200  0.20  18    16                                 step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                        0.16  5     1                              layer                                                                             step C.sub.2 H.sub.4                                                                              PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4) =                      PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 41                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________        First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                                                     0.19  7.5   4                                 step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                   First    B.sub.2 H.sub.6 /He = 1/100                                                                  → 3.75/1000                                    layer                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.4 /SiH.sub.4 = 3.75/1000                                                    0.20  18    12                                step B.sub.2 H.sub.6 /He = 1/100                                                                  → 0                                            Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1.5                           layer                                                                             step C.sub.2 H.sub.4                                                                              B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/3000                                                __________________________________________________________________________

                                      TABLE 42                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                                                     0.18  7     3                                 First                                                                              GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/1000                       step B.sub.2 H.sub.6 /He = 1/100                                                                  → 0                                            First                                                                             Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    15                            step                                                                              step                                                                          Third                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 0                                                            0.14  12    2                                 step B.sub.2 H.sub.6 /He = 1/100                                                                  → 1/4000                                       Second                                                                            Forth                                                                              SiH.sub.4 /He = 0.5                                                                    SiH.sub.4 = 200                                                                     C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                                                         0.16  5     1                             layer                                                                             step C.sub. 2 H.sub.4                                                                             B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4) =               B.sub.2 H.sub.6 /He = 1/100                                                                  1/4000                                                __________________________________________________________________________

                  TABLE 43                                                        ______________________________________                                        Sample No.                                                                             4301    4302   4303 4304 4305  4306 4307                             ______________________________________                                        Thickness (μ)                                                                       0.1     0.5    1.5  2    3     4    5                                Evaluation                                                                             Δ ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                            ○                                                                           Δ                          ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                  TABLE 44                                                        ______________________________________                                        Sample No.                                                                            4401    4402   4403  4404 4405  4406 4407                             ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                            1/10    2/10   4/10  5/10 10/10 2/1  3/1                              Flow ratio                                                                    Evaluation                                                                            ○                                                                              ⊚                                                                     ⊚                                                                    ○                                                                           ○                                                                            ○                                                                           Δ                          ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                                      TABLE 45                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/100000                                                     0.18  8     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    16                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                   0.16  5     0.5                                    PH.sub.3 /He = 1/30000                                               __________________________________________________________________________

                                      TABLE 46                                    __________________________________________________________________________    Layer                                                                             Layer                                                                              Gas      Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing     amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                                                     0.18  8     2                                      B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                                            →0.5/40                                            Second                                                                             SiH.sub.4 /He = 1                                                                            O.sub.2 /SiH.sub.4 = 0.5/40 → 0                    step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                                                     0.19  8     2                                      O.sub.2 /He = 0.5                                                        Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 SiH.sub. 4 = 1/100000                     step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200   0.16  12    16                            Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                   0.16  5     0.5                                    PH.sub.3 /He = 1/100                                                                         1/30000                                               __________________________________________________________________________

                                      TABLE 47                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     O.sub.2 /SiH.sub.4 = 5/1000 → 0                                                    0.18  8     4                                      O.sub.2 /He = 0.5                                                        Second                                                                        step SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    15                                Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 =                              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     1/100000    0.16  12    1                             Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub. 6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                           0.16  5     0.5                                    B.sub.2 H.sub.6 /He = 1/100                                                                  1/100000                                              __________________________________________________________________________

                                      TABLE 48                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 1/3               layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/1000                                                        0.16  7     8                                     B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 4/4000                                    O.sub.2 /He = 0.5                                                                            →0.25/4000                                         Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     O.sub.2 SiH.sub.4 = 0.25/4000                                                              0.18  8     16                               step O.sub.2 /He = 0.5                                                                            →1.5/4000                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                             0.16  5     0.5                                   B.sub.2 H.sub.6 /He = 1/100                                                                  1.5/4000                                              __________________________________________________________________________

                                      TABLE 49                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.18  8     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     O.sub.2 SiH.sub.4 = 1/400                                                                 0.18  9     16                                step O.sub.2 /He = 0.5                                                    Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub. 4)                                                  0.16  4     0.5                                    PH.sub.3 /He = 1/100                                                                         1/3000                                                         O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 1/400                            __________________________________________________________________________

                                      TABLE 50                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000 →                                              0.18  8     4                                      B.sub.2 H.sub.5 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40                                      O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    16                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          (O.sub.2 + C.sub.2 H.sub.4)/SiH.sub.4 = 3/10          layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4                                                    0.17  5     0.5                                    PH.sub.3 /He = 1/100                                                                         O.sub.2) = 1/30000                                             O.sub.2 /He = 0.5                                                    __________________________________________________________________________

                                      TABLE 51                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.18  8     2                                      B.sub.2 H.sub.6 /He = 1/100                                                                  →7/1600                                                 O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 1/40 →                                            0.5/40                                                    Second                                                                             SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 7/1600 →              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     3.75/1000   0.19  8     2                                      O.sub.2 /He = 0.5                                                                            O.sub.2 /SiH.sub.4 = 0.5/40 → 0                    Third                                                                              SiH.sub. 4 /He = 1                                                                           B.sub.2 H.sub.6 /SiH.sub.4 =                              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     3.75/1000 → 0                                                                      0.20  18    16                            Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                   0.16  5     0.5                                    PH.sub.3 /He = 1/100                                                                         1/3000                                                __________________________________________________________________________

                                      TABLE 52                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 4/4000 →                                              0.18  9     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  O.sub.2 /SiH.sub.4 = 1/40 → 0                           O.sub.2 /He = 0.5                                                        Second                                                                        step SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    14                                Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 0                            step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     →1/4000                                                                            0.18  16    2                             Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                            0.16  5     0.5                                    B.sub.2 H.sub.6 /He = 1/100                                                                  1/4000                                                __________________________________________________________________________

                  TABLE 53                                                        ______________________________________                                        Sample No. 5301    5302   5303 5304 5305 5306 5307                            ______________________________________                                        Thickness of                                                                             0.1     0.5    1.5  2    3    4    5                               second layer (μ)                                                           Evaluation Δ ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                           ○                                                                           Δ                         ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                  TABLE 54                                                        ______________________________________                                        Sample No.                                                                            5401    5402   5403  5404 5405  5406 5407                             ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                            1/10    2/10   4/10  5/10 10/10 2/1  3/1                              Flow ratio                                                                    Evaluation                                                                            ○                                                                              ⊚                                                                     ⊚                                                                    ○                                                                           ○                                                                            ○                                                                           Δ                          ______________________________________                                         ⊚: Excellent                                                   ○: Good                                                                Δ: Applicable for practical use                                    

                                      TABLE 55                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/100000                                                     0.18  8     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40                                     NH.sub.3 /He = 0.5                                                       Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200   0.20  18    16                                step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                   0.16  5     0.5                                    PH.sub.3 /He = 1/100                                                                         = 1/30000                                             __________________________________________________________________________

                                      TABLE 56                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                                                     0.18  8     2                                      B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40                                     NH.sub.3 /He = 0.5                                                                           → 0.5/40                                           Second                                                                             SiH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 0.5/40                              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     → 0  0.19  18    2                                      NH.sub.3 /He = 0.5                                                                           B.sub.2 H.sub.6 /SiH.sub.4 = 1/100000                     Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub. 6 /SiH.sub.4                               step B.sub.2 H.sub.4 /He = 1/100                                                            SiH.sub.4 = 200                                                                     = 1/100000  0.16  5     16                            Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                   0.16  5     0.5                                    PH.sub.3 /He = 1/100                                                                         = 1/30000                                             __________________________________________________________________________

                                      TABLE 57                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     NH.sub.3 /SiH.sub.4 = 5/1000                                                              0.18  8     4                                      NH.sub.3 /He = 0.5                                                                           → 0                                                Second                                                                             SiH.sub.4 /He = 1                                                        step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200   0.20  18    15                                Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4                                step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     = 1/100000  0.16  12    1                             Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub. 4 = 200                                                                    B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                            0.16  5     0.5                                    B.sub.2 H.sub.6 /He                                                                          = 1/10000                                                      = 1/100                                                              __________________________________________________________________________

                                      TABLE 58                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 1/3               layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 1/1000                                                        0.16  7     8                                     B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 4/4000                                   NH.sub.3 /He = 0.5                                                                           → 0.25/4000                                        Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     NH.sub.3 /SiH.sub.4 = 0.25/4000                                                            0.18  8     16                               step NH.sub.3 /He = 0.5                                                                           → 1.5/4000                                     Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                             0.16  5     0.5                                   B.sub.2 H.sub.6 /He = 1/100                                                                  = 1.5/4000                                            __________________________________________________________________________

                                      TABLE 59                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                       0.18  8     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40                                     NH.sub.3 /He = 0.5                                                       Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     NH.sub.3 /SiH.sub.4 = 1/400                                                               0.18  9     16                                step NH.sub.3 /He = 0.5                                                   Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.                                                     0.16  4     0.5                                    PH.sub.3 /He = 1/100                                                                         = 1/30000                                                      NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/400                           __________________________________________________________________________

                                      TABLE 60                                    __________________________________________________________________________    Layer                                                                             Layer         Flow               Discharg-                                                                           Deposition                                                                          Layer                        consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow         ing power                                                                           speed thickness                    tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio        (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                       __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000 →                                               0.18  8     4                                     B.sub.2 H.sub.6 /He = 1/100                                                                  NH.sub.3 /SiH.sub.4 = 1/40                                     NH.sub.3 /He = 0.5                                                       Second                                                                             SiH.sub.4 /He = 1                                                                      SiH.sub.4 = 200    0.20  18    16                               step                                                                      Second                                                                            Third                                                                              SiH.sub.4 /He = 0.5                                                                          (NH.sub.3 + C.sub.2 H.sub.4)/SiH.sub.4                layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     = 3/10       0.17  5     0.5                                   PH.sub.3 /He = 1/100                                                                         PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4                         NH.sub.3 /He = 0.5                                                                           + O.sub.2) = 1/30000                                  __________________________________________________________________________

                                      TABLE 61                                    __________________________________________________________________________    Layer                                                                             Layer         Flow                Discharg-                                                                           Deposition                                                                          Layer                       consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow          ing power                                                                           speed thickness                   tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio         (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                      __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 5/1000                                                         0.18  8     2                                    B.sub.2 H.sub.6 /He = 1/100                                                                  → 7/1600                                                NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/40 → 0.5/40                Second                                                                             SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 7/1600                       step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     → 3.75/1000                                                                          0.19  8     2                                    NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 0.5/40 → 0                   Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 =                              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     3.75/1000 → 0                                                                        0.20  18    16                          Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     PH.sub.3 /(SiH.sub.4 + C.sub.2 H.sub.4)                                                     0.16  5     0.5                                  PH.sub.3 /He = 1/100                                                                         = 1/30000                                             __________________________________________________________________________

                                      TABLE 62                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /SiH.sub.4 = 4/4000                                                       0.18  9     4                                      B.sub.2 H.sub.6 /He = 1/100                                                                  → 0                                                     NH.sub.3 /He = 0.5                                                                           NH.sub.3 /SiH.sub.4 = 1/40 → 0                     Second                                                                             SiH.sub.4 /He = 1                                                        step          SiH.sub.4 = 200   0.20  18    14                                Third                                                                              SiH.sub.4 /He = 0.5                                                                          B.sub.2 H.sub.6 /SiH.sub.4 =                              step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200                                                                     0 → 1/4000                                                                         0.18  16    2                             Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                            0.16  5     0.5                                    B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/4000                                              __________________________________________________________________________

                                      TABLE 63                                    __________________________________________________________________________    Layer                                                                             Layer         Flow              Discharg-                                                                           Deposition                                                                          Layer                         consti-                                                                           preparing                                                                          Gas      amount                                                                              Flow        ing power                                                                           speed thickness                     tution                                                                            steps                                                                              Used     (SCCM)                                                                              ratio       (W/cm.sup.2)                                                                        (Å/sec)                                                                         (μ)                        __________________________________________________________________________    First                                                                             First                                                                              SiH.sub.4 /He = 1                                                                            GeH.sub.4 /SiH.sub.4 = 1/1 → 0                 layer                                                                             step GeH.sub.4 /He = 1                                                                      SiH.sub.4 = 200                                                                     NH.sub.3 /SiH.sub.4 = 1/50                                                                0.20  8     2                                      NH.sub.3       O.sub.2 /SiH.sub.4 = 1/200                                     O.sub.2 /He = 0.5                                                        Second                                                                             SiH.sub.4 /He = 1                                                                            NH.sub.3 /SiH.sub.4 = 1/100                               step NH.sub.3 SiH.sub.4 = 200                                                                     O.sub.2 /SiH.sub.4 = 1/1000                                                               0.20  18    2                                      O.sub.2 /He = 0.5                                                        Third                                                                              SiH.sub.4 /He = 1                                                                            B.sub.2 H.sub.6 /SiH.sub.4 = 1/10000                      step B.sub.2 H.sub.6 /He = 1/100                                                            SiH.sub.4 = 200   0.14  12    16                            Second                                                                            Fourth                                                                             SiH.sub.4 /He = 0.5                                                                          C.sub.2 H.sub.4 /SiH.sub.4 = 3/10                     layer                                                                             step C.sub.2 H.sub.4                                                                        SiH.sub.4 = 200                                                                     B.sub.2 H.sub.6 /(SiH.sub.4 + C.sub.2 H.sub.4)                                            0.16  5     0.5                                    B.sub.2 H.sub.6 /He = 1/100                                                                  = 1/10000                                             __________________________________________________________________________

                  TABLE 64                                                        ______________________________________                                        Sample No.  6401   6402   6403 6404 6405 6406 6407                            ______________________________________                                        Thickness of                                                                  second layer (μ)                                                                       0.1    0.5    1.5  2    3    4    5                               Evaluation  Δ                                                                              ○                                                                             ⊚                                                                   ⊚                                                                   ○                                                                           ○                                                                           Δ                         ______________________________________                                          ⊚ : Excellent                                                  ○ : Good                                                              Δ: Applicable for practical use                                    

                  TABLE 65                                                        ______________________________________                                        Sample No.                                                                            6501    6502   6503  6504 6505  6506 6507                             ______________________________________                                        C.sub.2 H.sub.4 /SiH.sub.4                                                    Flow ratio                                                                            1/10    2/10   4/10  5/10 10/10 2/1  3/1                              Evaluation                                                                            ○                                                                              ⊚                                                                     ⊚                                                                    ○                                                                           ○                                                                            ○                                                                           Δ                          ______________________________________                                          ⊚ : Excellent                                                  ○ : Good                                                              Δ: Applicable for practical use                                    

What we claim is:
 1. An electrophotographic process comprising the stepsof:(a) charging a light receiving member comprising a substrate and alight receiving layer disposed on said substrate; said light receivinglayer comprising (a) a 1 to 100 μm thick first layer havingphotoconductivity and (b) a 0.003 to 30 μm thick second layer insequence from the side of the substrate; said first layer (a) comprising(i) am amorphous material containing silicon atoms as the mainconstituent, (ii) 1 to 6×10⁵ atomic ppm of germanium atoms, (iii) atleast one atom selected from hydrogen atoms and halogen atoms in a totalamount of 0.01 40 atomic %, (iv) a conductivity controlling elementselected from the group consisting of Group III and V elements of thePeriodic Table, and (v) at least one atom selected from the groupconsisting of oxygen atoms and nitrogen atoms, wherein said germaniumatoms being so distributed in the thickness direction that theconcentration thereof is enhanced at the position adjacent to thesubstrate and the concentration thereof is reduced or made substantiallyzero at the position adjacent to the interface with said second layer(b); wherein said second layer (b) comprises (b-i) an amorphous materialcontaining silicon atoms, (b-ii) 0.001 to 90 atomic % of carbon atoms,and (b-iii) 1.0 to 1×10⁴ atomic ppm of one atom selected from Group IIIand V atoms of the Periodic Table and does not contain germanium atoms;and (b) irradiating said light receiving member with an electromagneticwave carrying information, thereby forming electrostatic image.